Filed Pursuant to Rule 424(b)(3)
Registration No. 333-219196

The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying base prospectus are not an offer to sell and are not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED NOVEMBER 6, 2017

PROSPECTUS    SUPPLEMENT

(To prospectus dated November 6, 2017)

Summit Midstream Partners, LP

Units

    % Series A Fixed-to-Floating Rate Cumulative Redeemable

Perpetual Preferred Units

(Liquidation Preference $             per unit)

We are selling              of our     % Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units, liquidation preference $              per unit, representing limited partner interests in Summit Midstream Partners, LP (“Series A Preferred Units”) in this offering.

Distributions on the Series A Preferred Units are cumulative and compounding from the date of original issue and will be payable semi-annually in arrears on the      day of              and              through and including                  , 2022 and, thereafter, quarterly in arrears on the      day of             ,             ,             and              of each year, when, as and if declared by our general partner. A pro-rated initial distribution on the Series A Preferred Units offered hereby will be payable on                      , 2017 in an amount equal to approximately $              per Series A Preferred Unit. Distributions on the Series A Preferred Units will be payable out of amounts legally available therefor from and including the date of original issue to, but not including,                  , 2022, at a rate equal to     % per annum of the $              liquidation preference. On and after                  , 2022, distributions on the Series A Preferred Units will accumulate for each distribution period at a percentage of the $             liquidation preference equal to the three-month LIBOR plus a spread of     %.

At any time on or after                  , 2022, we may redeem the Series A Preferred Units, in whole or in part, at the redemption prices set forth and as described under the caption “Description of Our Series A Preferred Units—Redemption—Optional Redemption on or after                  , 2022” plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of redemption, whether or not declared. In addition, upon the occurrence of certain rating agency events as described under “Description of Our Series A Preferred Units—Redemption—Optional Redemption upon a Ratings Event,” we may redeem the Series A Preferred Units, in whole but not in part, at a price of $              per Series A Preferred Unit plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of redemption, whether or not declared. If a change of control triggering event, as described under “Description of Our Series A Preferred Units—Change of Control Triggering Event,” occurs, each holder of our Series A Preferred Units may require us to repurchase all or a portion of such holder’s Series A Preferred Units at a purchase price of $              per Series A Preferred Unit (101% of the liquidation preference) plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of settlement.

The Series A Preferred Units will rank, as to the payment of distributions and amounts payable on a liquidation event, senior to our common units.

Investing in our Series A Preferred Units involves risks. See “Risk Factors” on page S-16 of this prospectus supplement.

Delivery of the Series A Preferred Units is expected to be made on or about                      , 2017.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying base prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Joint Book-Running Managers

Prospectus supplement dated                     , 2017.

TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT

We expect that delivery of the Series A Preferred Units will be made to investors on or about                     , 2017, which will be the third business day following the date of this prospectus supplement (such settlement being referred to as “T+3”). Under Rule 15c6-1 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), trades in the secondary market are required to settle in two business days, unless the parties to any such trade expressly agree otherwise. Purchasers who wish to trade Series A Preferred Units on any date prior to the business day before delivery will be required, by virtue of the fact that the Series A Preferred Units initially settle in T+3, to specify an alternate settlement arrangement at the time of any such trade to prevent a failed settlement. Purchasers of the Series A Preferred Units who wish to trade the Series A Preferred Units on any date prior to the business day before delivery should consult their advisors.

S-i

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is the prospectus supplement, which describes our business and the specific terms of this offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference in this prospectus supplement and the accompanying prospectus. The second part is the accompanying base prospectus, which provides more general information about the securities we may offer from time to time, some of which do not apply to this offering of Series A Preferred Units. Generally, when we use the term “prospectus,” we are referring to both parts combined. If the information varies between this prospectus supplement and the accompanying base prospectus, you should rely on the information in this prospectus supplement.

In making an investment decision, prospective investors must rely on their own examination of us and the terms of the offering, including the merits and risks involved. None of Summit Midstream Partners, LP, the underwriters or any of their respective representatives is making any representation to you regarding the legality of an investment in the Series A Preferred Units described herein by you under applicable laws. You should consult with your own advisors as to legal, tax, business, financial and related aspects of an investment in our Series A Preferred Units.

Any statement made in this prospectus supplement or in a document incorporated or deemed to be incorporated by reference into this prospectus supplement will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement or in any other subsequently filed document that is also incorporated by reference into this prospectus supplement modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. Please read “Where You Can Find More Information” in this prospectus supplement.

Neither we nor any underwriter has authorized anyone to provide you with any information or to make any representations other than those contained or incorporated by reference in this prospectus supplement or the accompanying base prospectus. If anyone provides you with additional, different or inconsistent information, you should not rely on it. You should not assume that the information contained in this prospectus supplement, the accompanying base prospectus or any free writing prospectus is accurate as of any date other than the dates shown in these documents or that any information we have incorporated by reference herein is accurate as of any date other than the date of the applicable document incorporated by reference. Our business, financial condition, results of operations and prospects may have changed since such dates. We are offering to sell the Series A Preferred Units, and seeking offers to buy the Series A Preferred Units, only in jurisdictions where such offers and sales are permitted.

S-ii

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

S-10

S-11

S-12

S-13

S-14

S-15

RISK FACTORS

Before making an investment in the Series A Preferred Units offered hereby, you should carefully consider the risk factors discussed herein and included in Item 1A. “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2016, which is incorporated by reference herein, together with all of the other information included or incorporated by reference in this prospectus supplement and the accompanying base prospectus. If any of these risks were to occur, our business, financial condition or results of operations could be materially adversely affected.

Risks Related to the Series A Preferred Units

The Series A Preferred Units represent perpetual equity interests in us, and investors should not expect us to redeem the Series A Preferred Units on the date the Series A Preferred Units become redeemable by us or on any particular date afterwards.

The Series A Preferred Units represent perpetual equity interests in us, and they have no maturity or mandatory redemption date and, other than as the result of a Change of Control Triggering Event, are not redeemable at the option of investors. As a result, unlike our indebtedness, the Series A Preferred Units will not give rise to a claim for payment of a principal amount at a particular date. Instead, the Series A Preferred Units may be redeemed by us at our option (i) following the occurrence of a Ratings Event, in whole but not in part, out of funds legally available for such redemption, at a redemption price in cash of $         per Series A Preferred Unit plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of redemption, whether or not declared, or (ii) at any time on or after                  , 2022, in whole or in part, out of funds legally available for such redemption, at the redemption prices set forth under the caption “Description of Our Series A Preferred Units—Redemption—Optional Redemption on or after                  , 2022” plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of redemption, whether or not declared. Any decision we may make at any time to redeem the Series A Preferred Units will depend upon, among other things, our evaluation of our capital position and general market conditions at that time. In addition, the instruments governing our outstanding indebtedness may limit our ability to redeem the Series A Preferred Units.

As a result, holders of the Series A Preferred Units may be required to bear the financial risks of an investment in the Series A Preferred Units for an indefinite period of time. Moreover, holders of the Series A Preferred Units will not have any rights of conversion or exchange for other securities in us. The Series A Preferred Units will rank junior to all our current and future indebtedness. The Series A Preferred Units will also rank junior to any other Senior Securities we may issue in the future with respect to assets available to satisfy claims against us.

We cannot assure you that we will be able to pay distributions on our Series A Preferred Units regularly, and the agreements governing our indebtedness may limit the cash available to make distributions on the Series A Preferred Units.

Pursuant to our partnership agreement, we distribute all of our “available cash” each quarter to our limited partners. Our partnership agreement defines “available cash” to generally mean, for each fiscal quarter, all cash and cash equivalents on hand at the end of such quarter and all additional cash and cash equivalents on hand immediately prior to the date of determination of available cash resulting from borrowings for working capital purposes subsequent to the end of such quarter less the amount of cash reserves established by our general partner to:

S-16

Further, our existing debt agreements also may limit our ability to pay distributions on the Series A Preferred Units.

As a result, we do not expect to accumulate significant amounts of cash. Depending on the timing and amount of our cash distributions, these distributions could significantly reduce the cash available to us in subsequent periods to make payments on the Series A Preferred Units.

The Series A Preferred Units are subordinated to our existing and future debt obligations, and your interests could be diluted by the issuance of additional units pari passu with or senior to the Series A Preferred Units, and by other transactions.

The Series A Preferred Units are subordinated to all of our existing and future indebtedness (including indebtedness outstanding under our revolving credit facility, our fixed-rate senior notes and any other Senior Securities we may issue in the future with respect to assets available to satisfy claims against us). As of September 30, 2017, on a pro forma basis after giving effect to the estimated net proceeds of this offering as described in “Use of Proceeds,” we estimate that our total debt would have been approximately $         million and we would have had the ability to borrow an additional $         million under our revolving credit facility, subject to certain limitations. The payment of principal and interest on our debt reduces the cash available for distribution to holders of our units, including the Series A Preferred Units.

The issuance of additional Parity Securities or Senior Securities would dilute the interests of the holders of the Series A Preferred Units, and any issuance of Senior Securities or Parity Securities or additional indebtedness could affect our ability to pay distributions on, redeem or pay the liquidation preference on the Series A Preferred Units.

As a holder of Series A Preferred Units you will have limited voting rights.

Your voting rights as a holder of Series A Preferred Units will be limited. The holders of the Series A Preferred Units will be entitled to certain limited protective voting rights described in this prospectus supplement under “Description of Our Series A Preferred Units—Voting Rights.” Although holders of Series A Preferred Units will have limited voting rights, with respect to certain matters, the Series A Preferred Units will generally vote separately as a class along with any other series of our Parity Securities that we may issue following this offering upon which like voting rights have been conferred and are exercisable. As a result, the voting rights of holders of Series A Preferred Units may be significantly diluted, and the holders of such other series of Parity Securities that we may issue may be able to control or significantly influence the outcome of any vote.

Our ability to issue Parity Securities in the future could adversely affect the rights of holders of our Series A Preferred Units.

We are allowed to issue a certain amount of Parity Securities without the consent of the holders of the Series A Preferred Units, except where the cumulative distributions on the Series A Preferred Units or any Parity Securities are in arrears. See “Description of Our Series A Preferred Units—Voting Rights.” The issuance of any Parity Securities would have the effect of reducing the amounts available to the holders of the Series A Preferred Units issued in this offering upon our liquidation, dissolution or winding up if we do not have sufficient funds to pay all liquidation preferences of the Series A Preferred Units and Parity Securities in full. It also would reduce amounts available to make distributions on the Series A Preferred Units issued in this offering if we do not have

S-17

sufficient funds to pay distributions on all outstanding Series A Preferred Units and Parity Securities. In addition, future issuances and sales of Parity Securities, or the perception that such issuances and sales could occur, may cause prevailing market prices for the Series A Preferred Units to decline and may adversely affect our ability to raise additional capital in the financial markets at times and prices favorable to us.

A change in the rating of the Series A Preferred Units could adversely affect the market price of the Series A Preferred Units.

In connection with this offering, we expect that the Series A Preferred Units will receive a below- investment-grade credit rating from Moody’s and S&P. Rating agencies revise their ratings from time to time and could lower or withdraw any rating issued with respect to the Series A Preferred Units. Any real or anticipated downgrade or withdrawal of any ratings of the Series A Preferred Units could have an adverse effect on the market price or liquidity of the Series A Preferred Units.

Ratings reflect only the views of the issuing rating agency or agencies and are not recommendations to purchase, sell or hold any particular security, including the Series A Preferred Units. In addition, ratings do not reflect market prices or suitability of a security for a particular investor, and any future rating of the Series A Preferred Units may not reflect all risks related to the Partnership and its business or the structure or market value of the Series A Preferred Units.

Increased regulatory oversight, changes in the method pursuant to which the LIBOR rates are determined and potential phasing out of LIBOR after 2021 may adversely affect the value of the Series A Preferred Units.

Regulators and law enforcement agencies in the United Kingdom and elsewhere are conducting civil and criminal investigations into whether the banks that contribute to the British Bankers’ Association (the “BBA”) in connection with the calculation of daily LIBOR may have been under-reporting or otherwise manipulating or attempting to manipulate LIBOR. A number of BBA member banks have entered into settlements with their regulators and law enforcement agencies with respect to this alleged manipulation of LIBOR. On July 27, 2017, the Financial Conduct Authority (the “FCA”) announced that it will no longer persuade or compel banks to submit LIBOR rates after 2021 (the “FCA Announcement”).

It is not possible to predict the effect of the FCA Announcement, any changes in the methods pursuant to which the LIBOR rates are determined and any other reforms to LIBOR that will be enacted in the U.K. and elsewhere, which may adversely affect the trading market for LIBOR-based securities or result in the phasing out of LIBOR as a reference rate for securities. In addition, any changes announced by the FCA, including the FCA Announcement, the ICE Benchmark Administration Limited (the independent administrator of LIBOR) or any other successor governance or oversight body, or future changes adopted by such body, in the method pursuant to which the LIBOR rates are determined may result in a sudden or prolonged increase or decrease in the reported LIBOR rates. If that were to occur, the level of distributions would be affected and, to the extent that the value of your Series A Preferred Units is affected by reported LIBOR rates, the value of the Series A Preferred Units may be materially affected. Further, if a LIBOR rate is not available on the applicable determination date, the terms of the Series A Preferred Units will require that we use alternative determination procedures including, under certain circumstances, if the Calculation Agent determines that the LIBOR base rate has been discontinued, then it will determine whether to use a substitute or successor base rate that it has determined in its sole discretion is most comparable to the LIBOR base rate, which may result in different than expected distributions and could materially affect the value of the Series A Preferred Units. Please read “Description of Our Series A Preferred Units—Distributions—Distribution Rate.”

S-18

The Series A Preferred Units are a new class of our securities and do not have an established trading market, which may negatively affect their market value and your ability to transfer or sell your units. In addition, the lack of a fixed redemption date for the Series A Preferred Units will increase your reliance on the secondary market for liquidity purposes.

The Series A Preferred Units are a new class of our securities and do not have an established trading market. In addition, since the securities have no stated maturity date, investors seeking liquidity will be limited to selling their units in the secondary market absent redemption by us. Although we have registered the offer and sale of the Series A Preferred Units under the Securities Act, we do not intend to apply for the listing of the Series A Preferred Units on any securities exchange or for the quotation of the Series A Preferred Units on any automated dealer quotation system. In addition, although the underwriters have informed us that they intend to make a market in the Series A Preferred Units, as permitted by applicable laws and regulations, they are not obligated to do so, and they may discontinue their market-making activities at any time without notice. Active markets for the Series A Preferred Units may not develop or, if developed, may not continue indefinitely. In the absence of active trading markets, you may not be able to transfer your Series A Preferred Units within the time or at the prices you desire. If an active trading market does develop, the Series A Preferred Units may trade at prices lower than the offering price. The trading price of the Series A Preferred Units would depend on many factors, including:

Market interest rates may adversely affect the value of the Series A Preferred Units, and the distribution payable on the Series A Preferred Units will vary on and after                  , 2022 based on market interest rates.

One of the factors that will influence the price of the Series A Preferred Units will be the distribution yield on the Series A Preferred Units (as a percentage of the price of the Series A Preferred Units) relative to market interest rates. An increase in market interest rates, which are currently at low levels relative to historical rates, may lead prospective purchasers of the Series A Preferred Units to expect a higher distribution yield, and higher interest rates would likely increase our borrowing costs and potentially decrease funds available for distribution. Accordingly, higher market interest rates could cause the market price of the Series A Preferred Units to decrease.

In addition, on and after                  , 2022, distributions on the Series A Preferred Units will accumulate for each distribution period at a percentage of the $         liquidation preference equal to the then-current three-month LIBOR plus a spread of         %. The per annum distribution rate that is determined on the relevant determination date will apply to the entire quarterly distribution period following such determination date even if LIBOR increases during that period. As a result, holders of Series A Preferred Units will be subject to risks associated with fluctuation in interest rates and the possibility that holders will receive distributions that are lower than expected. We have no control over a number of factors, including economic, financial and political events, that impact market fluctuations in interest rates, which have in the past and may in the future experience volatility.

S-19

Holders of Series A Preferred Units may have liability to repay distributions.

Under certain circumstances, holders of the Series A Preferred Units may have to repay amounts wrongfully returned or distributed to them. Under Section 17-607 of the Delaware Revised Uniform Limited Partnership Act, we may not make a distribution if the distribution would cause our liabilities to exceed the fair value of our assets. Liabilities to partners on account of their limited partner interests and liabilities that are non-recourse to the partnership are not counted for purposes of determining whether a distribution is permitted.

Delaware law provides that for a period of three years from the date of an impermissible distribution, limited partners who received the distribution and who knew at the time of the distribution that it violated Delaware law will be liable to the limited partnership for the distribution amount. A purchaser of Series A Preferred Units who becomes a limited partner is liable for the obligations of the transferring limited partner to make contributions to the Partnership that are known to such purchaser of units at the time it became a limited partner and for unknown obligations if the liabilities could be determined from our partnership agreement.

Treatment of distributions on our Series A Preferred Units as guaranteed payments for the use of capital creates a different tax treatment for the holders of our Series A Preferred Units than the holders of our common units.

The tax treatment of distributions on our Series A Preferred Units is uncertain. We will treat the holders of Series A Preferred Units as partners for tax purposes and will treat distributions on the Series A Preferred Units as guaranteed payments for the use of capital that will generally be taxable to the holders of Series A Preferred Units as ordinary income. Although a holder of Series A Preferred Units could recognize taxable income from the accrual of such a guaranteed payment even in the absence of a contemporaneous distribution, we anticipate accruing and making the guaranteed payment distributions semi-annually on the      day of                  and                  through                  , 2022, and quarterly on the          day of                 ,                 ,                  and                  thereafter. Because the guaranteed payment for each unit must accrue as income to a holder during the taxable year of the accrual, the guaranteed payment attributable to the period beginning                  and ending                  will accrue to the holder of record of a Series A Preferred Unit on for such period. Please read “Material U.S. Federal Income Tax Consequences—Tax Consequences of Unit Ownership—Treatment of Distributions on Series A Preferred Units.” If you are a taxpayer reporting your income using the accrual method or using a taxable year other than the calendar year, you should consult your tax advisor with respect to the consequences of our guaranteed payment distribution accrual and reporting convention.

Otherwise, the holders of Series A Preferred Units are generally not anticipated to share in our items of income, gain, loss or deduction, except to the extent necessary to provide, to the extent possible, the Series A Preferred Units with the benefit of the liquidation preference. Please read “Material U.S. Federal Income Tax Consequences—Tax Consequences of Unit Ownership—Limitations on Deductibility of Losses” and “Material U.S. Federal Income Tax Consequences—Tax Consequences of Unit Ownership—Allocation of Income, Gain, Loss and Deduction,” below. We will not allocate any share of its nonrecourse liabilities to the holders of Series A Preferred Units.

A holder of Series A Preferred Units will be required to recognize gain or loss on a sale of units equal to the difference between the holder’s amount realized and tax basis in the units sold. The amount realized generally will equal the sum of the cash and the fair market value of other property such holder receives in exchange for such Series A Preferred Units. Subject to general rules requiring a blended basis among multiple partnership interests, the tax basis of a Series A Preferred Unit will generally be equal to the sum of the cash and the fair market value of other property paid by the holder to acquire such Series A Preferred Unit. Gain or loss recognized by a holder on the sale or exchange of a Series A Preferred Unit held for more than one year generally will be taxable as long-term capital gain or loss. Because holders of Series A Preferred Units will not generally be allocated a share of our items of depreciation, depletion or amortization, it is not anticipated that such holders would be required to recharacterize any portion of their gain as ordinary income as a result of the recapture rules.

S-20

Investment in the Series A Preferred Units by tax-exempt investors, such as employee benefit plans and individual retirement accounts, and non-U.S. persons raises issues unique to them. Although the issue is not free from doubt, we will treat distributions to non-U.S. holders of the Series A Preferred Units as “effectively connected income” (which will subject holders to U.S. net income taxation and possibly the branch profits tax) that are subject to withholding taxes imposed at the highest effective tax rate applicable to such non-U.S. holders. If the amount of withholding exceeds the amount of U.S. federal income tax actually due, non-U.S. holders may be required to file U.S. federal income tax returns in order to seek a refund of such excess. The treatment of guaranteed payments for the use of capital to tax-exempt investors is not certain and such payments may be treated as unrelated business taxable income (“UBTI”) for federal income tax purposes. If you are a tax-exempt entity or a non-U.S. person, you should consult your tax advisor with respect to the consequences of owning our Series A Preferred Units.

We may not have the funds necessary to finance the repurchase of the Series A Preferred Units in connection with a Change of Control Offer required by the terms of the Series A Preferred Units.

Upon the occurrence of a Change of Control Triggering Event, the terms of the Series A Preferred Units will require us to make an offer to repurchase all such Series A Preferred Units at a purchase price equal to 101% of the liquidation preference plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of settlement. The holders of our existing senior notes have substantially the same put rights upon such change of control events, which would increase the amount of securities we would be required to offer to repurchase upon the occurrence of such events. As such, it is possible that we will not have sufficient funds, or the ability to raise sufficient funds, at the time of the change of control to make the required repurchase of the Series A Preferred Units and our existing senior notes. In addition, restrictions under our revolving credit facility or the indenture governing our senior notes may not allow us to make a repurchase upon a Change of Control Triggering Event. If we are unable to refinance our outstanding debt or otherwise obtain a waiver from the holders of such debt, we would be prohibited from repurchasing the Series A Preferred Units. In addition, certain important corporate events, such as leveraged recapitalizations that would increase the level of our indebtedness, would not constitute a Change of Control under the terms of the Series A Preferred Units. Because the definition of change of control under our revolving credit facility will differ from that under the terms of the Series A Preferred Units, there may be a change of control and resulting default under our revolving credit facility at a time when no change of control has occurred under the terms of the Series A Preferred Units. Please read “Description of Our Series A Preferred Units—Change of Control Triggering Event.”

S-21

USE OF PROCEEDS

We expect to receive net proceeds of approximately $         million, after deducting the underwriting discount and commissions and estimated offering expenses, from the sale of the Series A Preferred Units offered hereby. We intend to use the net proceeds of sales of Series A Preferred Units offered hereby, after deducting the underwriting discount and estimated offering expenses, to repay outstanding borrowings under our revolving credit facility and for general partnership purposes, which may include, among other things, the repayment of other indebtedness, acquisitions and funding capital expenditures.

As of November 3, 2017 we had $526.0 million of borrowings and no letters of credit outstanding under our revolving credit facility with a weighted average interest rate of 3.75% and a May 2022 maturity date. A portion of the borrowings under our revolving credit facility was used to fund the drop down acquisition from SMP Holdings that closed in March 2016. Amounts repaid under our revolving credit facility may be reborrowed, subject to the terms of the facility.

Certain of the underwriters or their affiliates are lenders under our revolving credit facility, and as such, may receive a portion of the proceeds of sales of preferred units offered hereby to the extent any proceeds are used to repay borrowings under such facility. Please read “Underwriting.”

S-22

CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of September 30, 2017, on an actual basis and as adjusted to reflect this offering and the application of the estimated net proceeds as described under “Use of Proceeds.”

You should read our financial statements and notes thereto that are incorporated by reference into this prospectus supplement and the accompanying base prospectus for additional information about our capital structure.

S-23

DESCRIPTION OF OUR SERIES A PREFERRED UNITS

You can find the definitions of certain terms used in this description under the subheading “ —Certain Definitions.” In this description, the term “Company” refers only to Summit Midstream Holdings, LLC and not to any of its subsidiaries, the term “Finance Corp.” refers to Summit Midstream Finance Corp. and the terms “SMLP,” “we,” “us” and “our” refers only to Summit Midstream Partners, LP and not to any of its subsidiaries.

This “Description of Our Series A Preferred Units,” together with the “Description of Our Preferred Units” included in the accompanying base prospectus, is intended to be a useful overview of the material provisions of the Series A Preferred Units. Since this “Description of Our Series A Preferred Units” and the “Description of Our Preferred Units” in the base prospectus are only summaries, you should refer to our partnership agreement for a complete description of the Series A Preferred Units and your rights as holders of the Series A Preferred Units. This “Description of Our Series A Preferred Units” supersedes the “Description of Our Preferred Units” in the accompanying base prospectus to the extent they are inconsistent.

General

The Series A Preferred Units offered hereby are a new series of preferred units. In connection with the closing of this offering, we intend to adopt the Second Amended and Restated Agreement of Limited Partnership, which will set forth the terms of the Series A Preferred Units. Upon completion of this offering, there will be          Series A Preferred Units issued and outstanding. We may, without notice to or consent of the holders of the then-outstanding Series A Preferred Units, authorize and issue additional Junior Securities and, in certain circumstances, a certain amount of Parity Securities. Subject to the limitations described herein, we may in certain circumstances issue additional Parity Securities and Senior Securities. Please read “—Voting Rights.”

The holders of our common units and Series A Preferred Units are entitled to receive, to the extent permitted by law, such distributions as may from time to time be declared by our general partner. Upon any liquidation, dissolution or winding up of our affairs, whether voluntary or involuntary, the holders of our common units and Series A Preferred Units are entitled to receive distributions of our assets, after we have satisfied or made provision for our outstanding indebtedness and other obligations and after the payment to the holders of any class or series of limited partner interests having preferential rights to receive distributions of our assets over each such class of limited partner interests.

When issued and paid for in the manner described in this prospectus supplement and accompanying base prospectus, the Series A Preferred Units offered hereby will be fully paid and generally nonassessable. Subject to the matters described under “—Liquidation Rights,” each Series A Preferred Unit will generally have a fixed liquidation preference of $         per unit (subject to adjustment for any splits, combinations or similar adjustment to the Series A Preferred Units) plus an amount equal to accumulated and unpaid distributions thereon to, but not including, the date fixed for payment, whether or not declared. The rights of the holders of Series A Preferred Units to receive the liquidation preference will be subject to the proportional rights of holders of Parity Securities.

The Series A Preferred Units will represent perpetual equity interests in us and, unlike our indebtedness, will not give rise to a claim for payment of a principal amount at a particular date. As such, the Series A Preferred Units will rank junior to all of our current and future indebtedness and other liabilities with respect to assets available to satisfy claims against us.

All of the Series A Preferred Units offered hereby will be represented by one or more certificates issued to the Depositary (as defined under “—Book-Entry System”) and registered in the name of its nominee, and, so long as a Depositary has been appointed and is serving, no person acquiring Series A Preferred Units will be entitled to receive a certificate representing such Series A Preferred Units unless applicable law otherwise

S-24

requires or the Depositary gives notice of its intention to resign or is no longer eligible to act as such and a successor is not appointed within 60 days thereafter. Please read “—Book-Entry System.”

The Series A Preferred Units will not be convertible into our common units or any other securities and will not have exchange rights or be entitled or subject to any preemptive or similar rights. The Series A Preferred Units will not be subject to mandatory redemption or to any sinking fund requirements. The Series A Preferred Units will be subject to redemption at our option, in whole or in part, commencing on                  , 2022 or upon the occurrence of a Ratings Event. Please read “—Redemption—Optional Redemption on or after                  , 2022” and “—Redemption—Optional Redemption upon a Ratings Event.”

If a Change of Control Triggering Event occurs, each holder of the Series A Preferred Units may require us to repurchase all or a portion of such holder’s Series A Preferred Units at a purchase price equal to $         per Series A Preferred Unit (101% of the liquidation preference) plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of settlement. Please read “—Change of Control Triggering Event.”

We have appointed American Stock Transfer & Trust Company, LLC as the paying agent (the “Paying Agent”), and the registrar and transfer agent (the “Transfer Agent”) for the Series A Preferred Units. The address of the Paying Agent and the Transfer Agent is 6201 Fifteenth Avenue, Brooklyn, NY 11219.

Ranking

The Series A Preferred Units will, with respect to anticipated semi-annual or quarterly distributions and distributions upon the liquidation, winding up and dissolution of our affairs, rank:

Under our partnership agreement, we may issue Junior Securities from time to time in one or more series without the consent of the holders of the Series A Preferred Units. Our general partner has the authority to determine the preferences, powers, qualifications, limitations, restrictions and special or relative rights or privileges, if any, of any such series before the issuance of any units of that series. Our general partner will also determine the number of units constituting each series of securities. We have the ability under certain circumstances to issue a certain amount of Parity Securities. Our ability to issue Senior Securities is limited. Please read “—Voting Rights.”

Parity Securities with respect to the Series A Preferred Units may include classes of our securities that have different distribution rates, mechanics, periods (e.g., quarterly rather than semi-annual), payment dates or record dates than our Series A Preferred Units.

Liquidation Rights

We will liquidate in accordance with capital accounts. The capital account maintenance and allocation provisions are designed to provide to holders of our Series A Preferred Units and any Parity Securities, to the greatest extent possible, the benefit of their respective liquidation preferences. If necessary, the holders of outstanding Series A Preferred Units will be specially allocated items of our gross income and gain in a manner designed to achieve, in the event of any liquidation, dissolution or winding up of our affairs, whether voluntary or

S-25

involuntary, a liquidation preference of $         per unit. If the amount of our gross income and gain available to be specially allocated to the Series A Preferred Units is not sufficient to cause the capital account of a Series A Preferred Unit to equal the liquidation preference of a Series A Preferred Unit, then the amount that a holder of Series A Preferred Units would receive upon liquidation may be less than the Series A Preferred Unit liquidation preference. Any accumulated and unpaid distributions on the Series A Preferred Units and any Parity Securities will be paid prior to any distributions in liquidation made in accordance with capital accounts. The rights of the Series A Preferred Unitholders to receive the liquidation preference will be subject to the proportional rights of holders of any Parity Securities in liquidation. A consolidation or merger of us with or into any other entity, individually or in a series of transactions, will not be deemed to be a liquidation, dissolution or winding up of our affairs.

Voting Rights

The Series A Preferred Units will have no voting, consent or approval rights except as set forth below or as otherwise provided by Delaware law.

Unless we have received the affirmative vote or consent of the holders of at least two-thirds of the outstanding Series A Preferred Units, voting as a separate class, no amendment to our partnership agreement may be adopted that would have a material adverse effect on the existing preferences, rights, powers, duties or obligations of the Series A Preferred Units. For purposes of this voting requirement, among other things, any amendment to our partnership agreement (i) relating to the issuance of additional limited partner interests (subject to the voting rights regarding the issuance of certain amounts of Parity Securities or Senior Securities discussed below) and (ii) in connection with a merger or another transaction in which we are the surviving entity and the Series A Preferred Units remain outstanding with the terms thereof materially unchanged in any respect adverse to the holders of Series A Preferred Units, will be deemed to not materially adversely affect the powers, preferences, duties or special rights of the holders of Series A Preferred Units.

Except as provided below, unless we have received the affirmative vote or consent of the holders of at least two-thirds of the outstanding Series A Preferred Units, voting as a class together with holders of any other Parity Securities established after the closing of this offering and upon which like voting rights have been conferred and are exercisable, we may not:

S-26

With respect to the fifth bullet above, to the extent such an Event of Default with respect to a given action is cured in accordance with the terms of the Material Senior Indebtedness or waived by holders of the Material Senior Indebtedness, we will be deemed not to be in violation of our partnership agreement for failure to receive the affirmative vote or consent of the holders of two-thirds of the outstanding Series A Preferred Units with respect to taking such action. Further, on any matter described above in which the holders of the Series A Preferred Units are entitled to vote as a class (whether separately or together with the holders of any Parity Securities), such holders will be entitled to one vote per unit. Any Series A Preferred Units held by any of our subsidiaries or controlled affiliates will not be entitled to vote.

The consent of the holders of the Series A Preferred Units will not be required in connection with any Partnership Restructuring Event.

With respect to Series A Preferred Units that are held for a person’s account by another person (such as a broker, dealer, bank, trust company or clearing corporation, or an agent of any of the foregoing), in whose name such Series A Preferred Units are registered, such other person will, in exercising the voting rights in respect of such Series A Preferred Units on any matter, and unless the arrangement between such persons provides otherwise, vote such Series A Preferred Units in favor of, and at the direction of, the person who is the beneficial owner, and we will be entitled to assume it is so acting without further inquiry.

Distributions

General

Holders of Series A Preferred Units will be entitled to receive, when, as and if declared by our general partner out of legally available funds for such purpose, cumulative and compounding semi-annual or quarterly cash distributions, as applicable.

Distribution Rate

Distributions on Series A Preferred Units will be cumulative and compounding from the date of original issue and will be payable semi-annually in arrears (as described under “—Distribution Payment Dates”) to, but not including,                  , 2022 and, thereafter, quarterly in arrears, when, as and if declared by our general partner out of legally available funds for such purpose. A pro-rated initial distribution on the Series A Preferred Units will be paid on                 , 2017 in an amount equal to approximately $         per unit.

The initial distribution rate for the Series A Preferred Units during the Fixed Rate Period will be     % per annum of the $         liquidation preference per unit (equal to $        per unit per annum). During the Floating Rate Period, distributions on the Series A Preferred Units will accumulate for each distribution period at a percentage of the $         liquidation preference equal to the three-month LIBOR plus a spread of         %.

S-27

The Three-Month LIBOR Rate will be determined by the Calculation Agent (see “—Calculation Agent” below), as of the applicable Determination Date (as defined below), in accordance with the following provisions:

The Calculation Agent’s determination of any interest rate, and its calculation of the amount of interest for any interest period, will be on file at our principal offices, will be made available to any holder of Series A Preferred Units upon request and will be final and binding in the absence of manifest error.

All percentages resulting from any of the above calculations will be rounded, if necessary, to the nearest one hundred-thousandth of a percentage point, with five one-millionths of a percentage point rounded upwards (e.g., 9.876545% (or .09876545) being rounded to 9.87655% (or .0987655)) and all dollar amounts used in or resulting from such calculations will be rounded to the nearest cent (with one-half cent being rounded upwards).

S-28

Distribution Payment Dates

The “Distribution Payment Dates” for the Series A Preferred Units will be the                day of              and              of each year, commencing on                 , 2017 and continuing through the end of the Fixed Rate Period and on the      day of                 ,                 ,                  and                  of each year during the Floating Rate Period. Distributions will accumulate in each such period from and including the preceding Distribution Payment Date or the initial issue date, as the case may be, to but excluding the applicable Distribution Payment Date for such period, and distributions will accrue on accumulated distributions at the applicable distribution rate. If any Distribution Payment Date otherwise would fall on a day that is not a Business Day, declared distributions will be paid on the immediately succeeding Business Day without the accumulation of additional distributions. During the Fixed Rate Period, distributions on the Series A Preferred Units will be payable based on a 360-day year consisting of twelve 30-day months. During the Floating Rate Period, distributions on the Series A Preferred Units will be computed by multiplying the floating rate for that distribution period by a fraction, the numerator of which will be the actual number of days elapsed during that distribution period (determined by including the first day of the distribution period and excluding the last day, which is the distribution payment date), and the denominator of which will be 360, and by multiplying the result by the aggregate liquidation preference of the Series A Preferred Units.

Payment of Distributions

Not later than 5:00 p.m., New York City time, on each Distribution Payment Date, we will pay those semi-annual or quarterly distributions, if any, on the Series A Preferred Units that have been declared by our general partner to the holders of such Series A Preferred Units as such holders’ names appear on our unit transfer books maintained by the Registrar and Transfer Agent on the applicable record date. The record date for each distribution on our Series A Preferred Units will be the          Business Day of the month of the applicable Distribution Payment Date, except that in the case of payments of distributions in arrears, the record date with respect to a Distribution Payment Date will be such date as may be designated by our general partner in accordance with our partnership agreement.

So long as the Series A Preferred Units are held of record by the nominee of the Depositary, declared distributions will be paid to the Depositary in same-day funds on each Distribution Payment Date. The Depositary will credit accounts of its participants in accordance with the Depositary’s normal procedures. The participants will be responsible for holding or disbursing such payments to beneficial owners of the Series A Preferred Units in accordance with the instructions of such beneficial owners.

We will not declare, pay or set aside for payment full distributions on the Series A Preferred Units or any Parity Securities for any distribution period unless (i) full cumulative distributions have been paid on the Series A Preferred Units and any Parity Securities through the most recently completed distribution period for each such security and (ii) at the time of the declaration of the distribution on the Series A Preferred Units or Parity Securities, our general partner expects to have sufficient funds to pay the next distribution on the Series A Preferred Units and any Parity Securities in full (regardless of the relative timing of such distributions). To the extent distributions will not be paid in full on the Series A Preferred Units, the general partner will take appropriate action to ensure that all distributions declared and paid upon the Series A Preferred Units and any Parity Securities will be reduced, declared and paid on a pro rata basis on their respective payment dates.

We will not declare or pay or set aside for payment distributions on any Junior Securities (other than a distribution payable solely in Junior Securities) unless full cumulative distributions have been or contemporaneously are being paid on all outstanding Series A Preferred Units and any Parity Securities through the most recently completed respective distribution periods. To the extent a distribution period applicable to a class of Junior Securities or Parity Securities is shorter than the distribution period applicable to the Series A Preferred Units (e.g., quarterly rather than semi-annual), the general partner may declare and pay regular distributions with respect to such Junior Securities or Parity Securities so long as, at the time of declaration of

S-29

such distribution, the general partner expects to have sufficient funds to pay the full distribution in respect of the Series A Preferred Units on the next successive Distribution Payment Date.

Change of Control Triggering Event

If a Change of Control Triggering Event occurs, unless we have previously or concurrently exercised our right to redeem all of the Series A Preferred Units as described under “—Redemption—Optional Redemption upon a Ratings Event” and “—Redemption—Optional Redemption on or after                  , 2022,” each holder of the Series A Preferred Units may require us to repurchase all or a portion of such holder’s Series A Preferred Units at a purchase price (a “Change of Control Payment”) equal to $         per Series A Preferred Unit (101% of the liquidation preference) plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of settlement (the “Change of Control Settlement Date”). Any such redemption would be effected only out of funds legally available for such purposes and will be subject to compliance with the provisions of our outstanding indebtedness.

Within 30 days following any Change of Control Triggering Event, unless we have previously or concurrently exercised our right to redeem all of the Series A Preferred Units as described under “—Redemption—Optional Redemption upon a Ratings Event” and “—Redemption—Optional Redemption on or after                  , 2022,” we will mail a notice to each holder of Series A Preferred Units describing the transaction or transactions and identifying the ratings decline that, together, constitute the Change of Control Triggering Event, and offering to repurchase the Series A Preferred Units as of the Change of Control Settlement Date specified in the notice (a “Change of Control Offer”), which date will be no earlier than 30 days and no later than 60 days from the date such notice is mailed, pursuant to the procedures required by our partnership agreement and described in such notice.

We will comply with the requirements of Rule 14e-1 under the Exchange Act and any other securities laws and regulations thereunder to the extent those laws and regulations are applicable in connection with the repurchase of the Series A Preferred Units as a result of a Change of Control Triggering Event. To the extent that the requirements of any applicable securities laws or regulations conflict with the Change of Control Triggering Event provisions of our partnership agreement, we will comply with such securities laws and regulations and will not be deemed to have breached our obligations under the Change of Control Triggering Event provisions of our partnership agreement by virtue of such compliance.

Promptly following the expiration of the Change of Control Offer, we will, to the extent lawful, accept for payment all Series A Preferred Units or portions thereof properly tendered pursuant to the Change of Control Offer. Promptly thereafter on the Change of Control Settlement Date, we will deposit with the Paying Agent an amount equal to the Change of Control Payment in respect of all Series A Preferred Units or portions thereof properly tendered.

On the Change of Control Settlement Date, the Paying Agent will mail to each holder of Series A Preferred Units properly tendered the Change of Control Payment therefor (or, if all the Series A Preferred Units are then in uncertificated form, make such payment through the facilities of DTC). We will authenticate and mail to each holder of Series A Preferred Units a new certificate (if applicable), equal in principal amount to any unpurchased portion of the Series A Preferred Units surrendered, if any, or cause the same value to be transferred by book entry. We will publicly announce the results of the Change of Control Offer on or as soon as practicable after the Change of Control Settlement Date.

The holders of the Series A Preferred Units will not be able to require us to repurchase or redeem the Series A Preferred Units in the event of a takeover, recapitalization or similar transaction.

We will not be required to make a Change of Control Offer upon a Change of Control Triggering Event if (a) a third party makes the Change of Control Offer in the manner, at the time and otherwise in compliance

S-30

with the requirements set forth in our partnership agreement applicable to a Change of Control Offer made by us and purchases all Series A Preferred Units properly tendered and not withdrawn under the Change of Control Offer or (b) in connection with, or in contemplation of, any publicly announced Change of Control, we have made an offer to purchase (an “Alternate Offer”) any and all Series A Preferred Units validly tendered at a cash price equal to or higher than the Change of Control Payment and have purchased all Series A Preferred Units properly tendered in accordance with the terms of such Alternate Offer. Notwithstanding anything to the contrary contained in our partnership agreement, a Change of Control Offer may be made in advance of a Change of Control Triggering Event, and conditioned upon the consummation of such Change of Control Triggering Event if a definitive agreement is in place for the Change of Control Triggering Event at the time the Change of Control Offer is made.

The definition of Change of Control includes a phrase relating to the direct or indirect sale, lease, transfer, conveyance or other disposition of “all or substantially all” of the properties or assets of us and our Restricted Subsidiaries taken as a whole. Although there is a limited body of case law interpreting the phrase “substantially all,” there is no precise established definition of the phrase under applicable law. Accordingly, the ability of a holder of Series A Preferred Units to require us to repurchase our Series A Preferred Units as a result of a sale, lease, transfer, conveyance or other disposition of less than all of the properties or assets of our assets and those of our subsidiaries taken as a whole to another person or group may be uncertain.

If we fail to make a Change of Control Offer, to the extent required, or to repurchase any Series A Preferred Units tendered by holders for repurchase as required in connection with a Change of Control Triggering Event, then, from and after the first date of such failure and until such repurchase is made, the then-applicable distribution rate for the outstanding Series A Preferred Units will be         % per annum (an increase of 2.0% per annum) prior to                  , 2022, and on and after                  , 2022, will accumulate for each distribution period at a percentage of the liquidation preference equal to the three-month LIBOR plus a spread of         % (an increase of 2.0% per annum).

In the event that, upon consummation of a Change of Control Offer or Alternate Offer, less than 10% in aggregate principal amount of the Series A Preferred Units are held by holders other than us and our affiliates, we will have the right, upon not less than 30 nor more than 60 days’ prior notice, given not more than 30 days following the purchase pursuant to the Change of Control Offer or Alternate Offer described above, to redeem all of the Series A Preferred Units that remain outstanding following such purchase at a redemption price equal to the Change of Control Payment.

Redemption

Optional Redemption upon a Ratings Event

At any time within 120 days after the conclusion of any review or appeal process instituted by us following the occurrence of a Ratings Event (as defined below), we may, at our option, redeem the Series A Preferred Units in whole, but not in part, at a redemption price in cash per Series A Preferred Unit equal to $         (102% of the liquidation preference) plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date fixed for redemption, whether or not declared. Any such redemption would be effected only out of funds legally available for such purposes and will be subject to compliance with the provisions of our outstanding indebtedness.

Optional Redemption on or after                  , 2022

At any time on or after                  , 2022, we may redeem the Series A Preferred Units, at our option, in whole or in part, by paying the redemption price set forth below plus an amount equal to all accumulated and unpaid distributions thereon to, but not including, the date of redemption, whether or not declared. Any such redemption would be effected only out of funds legally available for such purposes and will be subject to compliance with the provisions of our outstanding indebtedness.

S-31

The redemption price shall be as follows (assuming such Series A Preferred Units are redeemed during the 12-month period beginning on                       of the years indicated below):

Redemption Procedures

We will give notice of any redemption not less than 30 days and not more than 60 days before the scheduled date of redemption, to the holders of any Series A Preferred Units to be redeemed as such holders’ names appear on our unit transfer books maintained by the Transfer Agent at the address of such holders shown therein. Such notice will state: (i) the redemption date, (ii) the number of Series A Preferred Units to be redeemed and, if fewer than all outstanding Series A Preferred Units are to be redeemed, the number (and, in the case of Series A Preferred Units in certificated form, the identification) of units to be redeemed from such holder, (iii) the redemption price, (iv) the place where any Series A Preferred Units in certificated form are to be redeemed and will be presented and surrendered for payment of the redemption price therefor and (v) that distributions on the units to be redeemed will cease to accumulate from and after such redemption date.

If fewer than all of the outstanding Series A Preferred Units are to be redeemed, the number of Series A Preferred Units to be redeemed will be determined by us, and such units will be redeemed by such method of selection as the Depositary (or, in the case of any certificated units, our general partner) determines, either pro rata or by lot, with adjustments to avoid redemption of fractional units. So long as all Series A Preferred Units are held of record by the nominee of the Depositary, we will give notice, or cause notice to be given, to the Depositary of the number of Series A Preferred Units to be redeemed, and the Depositary will determine the number of Series A Preferred Units to be redeemed from the account of each of its participants holding such units in its participant account. Thereafter, each participant will select the number of units to be redeemed from each beneficial owner for whom it acts (including the participant, to the extent it holds Series A Preferred Units for its own account). A participant may determine to redeem Series A Preferred Units from some beneficial owners (including the participant itself) without redeeming Series A Preferred Units from the accounts of other beneficial owners. Any Series A Preferred Units not redeemed will remain outstanding and entitled to all the rights and preferences of Series A Preferred Units under our partnership agreement.

So long as the Series A Preferred Units are held of record by the nominee of the Depositary, the redemption price will be paid by the Paying Agent to the Depositary on the redemption date. The Depositary’s normal procedures provide for it to distribute the amount of the redemption price in same-day funds to its participants who, in turn, are expected to distribute such funds to the persons for whom they are acting as agent.

If we give a notice of redemption, then we will deposit with the Paying Agent funds sufficient to redeem the Series A Preferred Units as to which notice has been given no later than 10:00 a.m., New York City time, on the date fixed for redemption, and we will give the Paying Agent irrevocable instructions and authority to pay the redemption price to the holder or holders thereof upon surrender or deemed surrender (which will occur automatically if the certificate representing such units is issued in the name of the Depositary or its nominee) of the certificates therefor. If notice of redemption has been given, then from and after the date fixed for redemption, unless we default in providing funds sufficient for such redemption at the time and place specified for payment pursuant to the notice, all distributions on such units will cease to accumulate and all rights of holders of such Series A Preferred Units with respect to such Series A Preferred Units will cease, except the right to receive the redemption price, plus an amount equal to accumulated and unpaid distributions to, but not including, the date fixed for redemption, whether or not declared, and such Series A Preferred Units may not thereafter be transferred on the books of the Transfer Agent or be deemed to be outstanding for any purpose whatsoever.

S-32

We will be entitled to receive from the Paying Agent the interest income, if any, earned on such funds deposited with the Paying Agent (to the extent that such interest income is not required to pay the redemption price of the Series A Preferred Units to be redeemed), and the holders of any Series A Preferred Units so redeemed will have no claim to any such interest income. Any funds deposited with the Paying Agent by us for any reason, including redemption of Series A Preferred Units, that remain unclaimed or unpaid after one year after the applicable redemption date or other payment date, will be, to the extent permitted by law, repaid to us upon our written request, after which repayment the holders of Series A Preferred Units entitled to such redemption or other payment will have recourse only to us.

If only a portion of the Series A Preferred Units represented by a certificate has been called for redemption, upon surrender of the certificate to the Paying Agent (which will occur automatically if the certificate representing such units is registered in the name of the Depositary or its nominee), we will issue and the Paying Agent will deliver to the holder of such units a new certificate (or adjust the applicable book-entry account) representing the number of Series A Preferred Units represented by the surrendered certificate that have not been called for redemption.

Notwithstanding any notice of redemption, there will be no redemption of any Series A Preferred Units called for redemption until funds sufficient to pay the full redemption price of such units, plus all accumulated and unpaid distributions to, but not including, the date of redemption, whether or not declared, have been deposited by us with the Paying Agent.

We and our affiliates may from time to time purchase Series A Preferred Units, subject to compliance with all applicable securities and other laws. Neither we nor any of our affiliates has any obligation, or any present plan or intention, to purchase any Series A Preferred Units. Any Series A Preferred Units that are redeemed or otherwise acquired by us will be cancelled.

Notwithstanding the foregoing, unless (i) full cumulative distributions have been or contemporaneously are being paid or provided for on all outstanding Series A Preferred Units and any Parity Securities through the most recently completed respective distribution periods and (ii) our general partner expects to have sufficient funds to pay the next distribution on the all outstanding Series A Preferred Units and any Parity Securities in full (regardless of the relative timing of such distributions), we may not repurchase, redeem or otherwise acquire, in whole or in part, any Series A Preferred Units or Parity Securities except pursuant to a purchase or exchange offer made on the same relative terms to all holders of Series A Preferred Units and any Parity Securities. Common units and any other Junior Securities may not be redeemed, repurchased or otherwise acquired unless full cumulative distributions have been or contemporaneously are being paid or provided for on all outstanding Series A Preferred Units and any Parity Securities through the most recently completed respective distribution periods.

No Limited Call Right

Our general partner’s limited call right referenced in “The Partnership Agreement—Limited Call Right” in the accompanying base prospectus will not apply to the Series A Preferred Units.

No Sinking Fund

The Series A Preferred Units will not have the benefit of any sinking fund.

No Fiduciary Duty

We and our general partner entities and their officers and directors will not owe any fiduciary duties to holders of the Series A Preferred Units.

S-33

Book-Entry System

All Series A Preferred Units offered hereby will be represented by one or more certificates issued to The Depository Trust Company (and its successors or assigns or any other depositary selected by us) (the “Depositary”), and registered in the name of its nominee (initially, Cede & Co.) , including Euroclear Bank S.A./N.V., as operator of the Euroclear System (“Euroclear”), and Clearstream Banking, société anonyme (“Clearstream”). The Series A Preferred Units offered hereby will continue to be represented by one or more certificates registered in the name of the Depositary or its nominee, and no holder of the Series A Preferred Units offered hereby will be entitled to receive a certificate evidencing such units unless otherwise required by law or the Depositary gives notice of its intention to resign or is no longer eligible to act as such and we have not selected a substitute Depositary within 60 calendar days thereafter. So long as the Depositary is appointed and serving, payments and communications made by us to holders of the Series A Preferred Units will be duly made by making payments to, and communicating with, the Depositary. Accordingly, unless certificates are available to holders of the Series A Preferred Units, each purchaser of Series A Preferred Units must rely on (i) the procedures of the Depositary and its participants to receive distributions, any redemption price, liquidation preference and notices, and to direct the exercise of any voting or nominating rights, with respect to such Series A Preferred Units and (ii) the records of the Depositary and its participants to evidence its ownership of such Series A Preferred Units. Interests held through Clearstream and Euroclear will be recorded on the Depositary’s books as being held by the United States depositary for each of Clearstream and Euroclear, which United States depositaries will in turn hold interests on behalf of their participants’ customers’ securities accounts.

So long as the Depositary (or its nominee) is the sole holder of the Series A Preferred Units, no beneficial holder of the Series A Preferred Units will be deemed to be a holder of Series A Preferred Units. The Depository Trust Company, the initial Depositary, is a New York-chartered limited purpose trust company that performs services for its participants, some of whom (and/or their representatives) own The Depository Trust Company. The Depositary maintains lists of its participants and will maintain the positions (i.e., ownership interests) held by its participants in the Series A Preferred Units, whether as a holder of the Series A Preferred Units for its own account or as a nominee for another holder of the Series A Preferred Units.

Euroclear has advised us that it was created in 1968 to hold securities for its participants and to clear and settle transactions between Euroclear participants through simultaneous electronic book-entry delivery against payment, thereby eliminating the need for physical movement of certificates and any risk from lack of simultaneous transfers of securities and cash. Euroclear provides various other services, including securities lending and borrowing, and interfaces with domestic markets in several countries. Euroclear is operated by Euroclear Bank SA/NV under contract with Euroclear plc, a United Kingdom corporation. Euroclear participants include banks, including central banks, securities brokers and dealers and other professional financial intermediaries. Indirect access to Euroclear is also available to other firms that clear through or maintain a custodial relationship with a Euroclear participant, either directly or indirectly.

Calculation Agent

We will appoint a calculation agent for the Series A Preferred Units prior to the commencement of the Floating Rate Period.

Certain Definitions

“Business Day” means Monday through Friday of each week, except that a legal holiday recognized as such by the government of the United States of America or the States of Texas or New York shall not be regarded as a Business Day.

“Change of Control” means the occurrence of any of the following:

S-34

Notwithstanding the preceding, a conversion of us or any of our Restricted Subsidiaries from a limited partnership, corporation, limited liability company or other form of entity to a limited liability company, corporation, limited partnership or other form of entity or an exchange of all of the outstanding equity interests in one form of entity for equity interests in another form of entity shall not constitute a Change of Control, so long as following such conversion or exchange the “persons” (as that term is used in Section 13(d)(3) of the Exchange Act) who beneficially owned our equity interests immediately prior to such transactions continue to beneficially own in the aggregate more than 50% of the voting interests of such entity, or continue to beneficially own sufficient equity interests in such entity to elect a majority of its directors, managers, trustees or other persons serving in a similar capacity for such entity or its general partner, as applicable, and, in either case no “person” beneficially owns more than 50% of the voting interests of such entity or its general partner, as applicable.

In addition, a Change of Control shall not occur as a result of (i) a merger between us and our general partner or (ii) any transaction in which the Company remains a subsidiary of us but one or more intermediate holding companies between the Company and us are added, liquidated, merged or consolidated out of existence.

“Change of Control Triggering Event” means the occurrence of a Change of Control that is accompanied or followed by a downgrade by one or more gradations (including both gradations within ratings categories and between ratings categories) or withdrawal of the rating of the Series A Preferred Units within the Ratings Decline Period by at least two of the rating agencies, as a result of which the rating of the Series A Preferred Units on any day during such Ratings Decline Period is below the rating by such rating agency in effect immediately preceding the first public announcement of the Change of Control (or occurrence thereof if such Change of Control occurs prior to public announcement).

“Determination Date” means the second London Business Day (as defined below) immediately preceding the first date of the applicable distribution period.

“Distribution Payment Date” means each of the          day of              and              through and including                  , 2022 and, thereafter, quarterly in arrears on the          day of             ,             ,              and              of each year.

S-35

“Fixed Rate Period” means the period of time from and including the date of original issue to, but not including,                  , 2022.

“Floating Rate Period” means the period of time beginning on and continuing after                  , 2022.

“Junior Securities” means our common units and each other class or series of limited partner interests or other equity securities established after the original issue date of the Series A Preferred Units that is not expressly made senior to or pari passu with the Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event.

“London Business Day” means any day on which dealings in deposits in U.S. dollars are transacted in the London interbank market.

“Material Senior Indebtedness” means (a) the indebtedness issued under that certain First Supplemental Indenture, dated as of July 15, 2014, by and among the Company, Finance Corp., the guarantors party thereto and U.S. Bank National Association, (b) the indebtedness issued under that certain Second Supplemental Indenture, dated as of February 15, 2017, by and among the Company, Finance Corp., the guarantors party thereto and U.S. Bank National Association and (c) any future indebtedness of the Company or Finance Corp. in an amount greater than $200,000,000 issued under a note indenture (and not under any loan or other credit agreement with commercial banking institutions).

“Parity Basket” means:

In determining availability under the Parity Basket, the aggregate amount of Series A Preferred Units and Parity Securities will be calculated on an as-if converted basis, with the Series A Preferred Units and any other non-convertible Parity Securities being treated as convertible into common units at a ratio equal to the purchase price of such Parity Securities divided by the volume-weighted average price of the common units for the preceding 30 trading days.

“Parity Securities” means any class or series of partnership interests or other equity securities established after the original issue date of the Series A Preferred Units that is not expressly made senior or subordinated to the Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event.

“Partnership Restructuring Event” means any restructuring, simplification or similar transaction or series of transactions that modifies, eliminates or otherwise restructures the general partner interest, the incentive distribution rights or the equity interests of our general partner or its affiliates, provided that the principal parties thereto are us, the owner of a majority of the equity interests in our general partner and/or its affiliates.

“Paying Agent” means American Stock Transfer & Trust Company, LLC as the paying agent for the Series A Preferred Units.

S-36

“Person” means any individual, corporation, partnership, joint venture, association, joint-stock company, trust, unincorporated organization, limited liability company or government or other entity.

“Qualifying Owners” means the collective reference to (i) Energy Capital Partners II, LP, Energy Capital Partners II-A, L.P., Energy Capital Partners II-B IP, LP, Energy Capital Partners II-C (Summit IP), LP, Energy Capital Partners II (Summit Co-Invest), LP, SMLP Holdings, LLC and each of their affiliated funds and investment vehicles and any fund manager, general partner, managing member or principal of any of the foregoing; (ii) the officers, directors and management employees of us, the Company and our subsidiaries; and (iii) any person controlled by any of the persons described in any of the clauses (i) or (ii).

“Ratings Decline Period” means the period that (i) begins on the occurrence of a Change of Control and (ii) ends 60 days following consummation of such Change of Control.

“Ratings Event” means a change by any nationally recognized statistical rating organization (within the meaning of Section 3(a)(62) of the Exchange Act) that publishes a rating for us (a “rating agency”) to its equity credit criteria for securities such as the Series A Preferred Units, as such criteria are in effect as of the original issue date of the Series A Preferred Units (the “current criteria”), which change results in (i) any shortening of the length of time for which the current criteria are scheduled to be in effect with respect to the Series A Preferred Units, or (ii) a lower equity credit being given to the Series A Preferred Units than the equity credit that would have been assigned to the Series A Preferred Units by such rating agency pursuant to its current criteria.

“Representative Amount” means an amount that, in the Calculation Agent’s judgment, is representative of a single transaction in the relevant market at the relevant time.

“Restricted Subsidiary” of a person means any subsidiary of the referent person that is not an Unrestricted Subsidiary. Notwithstanding anything to the contrary, the Company and Finance Corp. shall at all times be our Restricted Subsidiaries. Unless specified otherwise, references herein to a Restricted Subsidiary refer to our Restricted Subsidiaries.

“Reuters screen” means the display on the Thomson Reuters Eikon service, or any successor or replacement service.

“Senior Securities” means each other class or series of limited partner interests or other equity securities established after the original issue date of the Series A Preferred Units that is expressly made senior to the Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event.

“Three-Month LIBOR Rate” means LIBOR for each distribution period during the Floating Rate Period.

“Transfer Agent” means American Stock Transfer & Trust Company, LLC as the registrar and transfer agent for the Series A Preferred Units.

“Unrestricted Subsidiary” means any subsidiary of ours (other than Finance Corp. or the Company) that is designated by the board of directors of our general partner as an Unrestricted Subsidiary, but only to the extent that such subsidiary:

S-37

All subsidiaries of an Unrestricted Subsidiary shall also be Unrestricted Subsidiaries.

S-38

MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES

The tax consequences to you of an investment in our Series A Preferred Units will depend in part on your own tax circumstances. For a discussion of the material federal income tax considerations associated with our operations and the purchase, ownership and disposition of common units, please read “Material U.S. Federal Income Tax Consequences” in the accompanying base prospectus and “Tax Risks to Common Unitholders” in our most recent Annual Report on Form 10-K, which is incorporated by reference into this prospectus supplement. Although this section updates and adds information related to certain tax considerations with respect to the Series A Preferred Units, it also should be read in conjunction with the risk factors included under the caption “Tax Risks to Unitholders” in our most recent Annual Report on Form 10-K, “Risk Factors” in our most recent Quarterly Report on Form 10-Q, and “Material U.S. Federal Income Tax Consequences” in the accompanying base prospectus, which provides a discussion of the principal federal income tax considerations associated with our operations. The following discussion is limited as described under the caption “Material U.S. Federal Income Tax Consequences” in the accompanying base prospectus and as discussed below. You are urged to consult with your own tax advisor about the federal, state, local and non-U.S. tax consequences particular to your circumstances.

This section summarizes the material federal income tax consequences that may be relevant to prospective holders of Series A Preferred Units who are individual citizens or residents of the United States and, unless otherwise noted in the following discussion, is the opinion of Baker Botts L.L.P., counsel to us, insofar as it relates to matters of federal income tax law and legal conclusions with respect to those matters. Other than as set forth in “Taxation of the Partnership—Partnership Status,” the tax consequences and opinions set forth below are based upon the assumption that the Series A Preferred Units will be treated as partnership interests for federal income tax purposes. In addition, this section is based upon current provisions of the U.S. Internal Revenue Code of 1986, as amended (the “Code”), existing and proposed U.S. Treasury regulations thereunder (the “Treasury Regulations”), and current administrative rulings and court decisions, all of which are subject to change. Changes in these authorities may cause the federal income tax consequences to a prospective unitholder to vary substantially from those described below, possibly on a retroactive basis. Unless the context otherwise requires, references in this section to “we” or “us” are references to Summit Midstream Partners, LP and its subsidiaries.

The following discussion does not comment on all federal income tax matters affecting us or the holders of our Series A Preferred Units. Moreover, the discussion focuses on unitholders who are individual citizens or residents of the U.S. (for federal income tax purposes), who use the calendar year as their taxable year, who purchase Series A Preferred Units in this offering, who do not materially participate in the conduct of our business activities and who hold such units as capital assets (typically, property that is held for investment), and has only limited application to corporations, estates, entities treated as partnerships for U.S. federal income tax purposes, trusts, nonresident aliens, U.S. expatriates and former citizens or long-term residents of the United States or other unitholders subject to specialized tax treatment, such as banks, insurance companies and other financial institutions, tax-exempt institutions, foreign persons (including, without limitation, controlled foreign corporations, passive foreign investment companies and non-U.S. persons eligible for the benefits of an applicable income tax treaty with the U.S.), IRAs, real estate investment trusts (REITs) or mutual funds, dealers in securities or currencies, traders in securities, U.S. persons whose “functional currency” is not the U.S. dollar, persons holding their units as part of a “straddle,” “hedge,” “conversion transaction” or other risk reduction transaction, and persons deemed to sell their units under the constructive sale provisions of the Code. In addition, the discussion only comments to a limited extent on state, local and foreign tax consequences. Accordingly, we encourage each prospective unitholder to consult his own tax advisor in analyzing the state, local and foreign tax consequences particular to him of the ownership or disposition of our units and potential changes in applicable tax laws.

All statements as to matters of federal income tax law and legal conclusions with respect thereto, but not as to factual matters, contained in this section, unless otherwise noted, are the opinion of Baker Botts L.L.P. and are based on the accuracy of the representations made by us.

S-39

We will rely on opinions of Baker Botts L.L.P. An opinion of counsel represents only that counsel’s best legal judgment and does not bind the IRS or the courts. Accordingly, the opinions and statements made herein may not be sustained by a court if contested by the IRS. Any contest of this sort with the IRS may materially and adversely impact the market for the Series A Preferred Units and the prices at which the Series A Preferred Units trade. In addition, the costs of any contest with the IRS, principally legal, accounting and related fees, will result in a reduction in our cash available for distribution and thus will be borne indirectly by our unitholders and our general partner. Additionally, pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, for taxable years beginning after December 31, 2017, if the IRS makes an audit adjustment to any of our income tax returns, our unitholders will directly or indirectly bear any taxes (including any applicable penalties and interest) resulting from such audit adjustment (please read “—Administrative Matters—Information Returns and Audit Procedures”). Furthermore, the tax treatment of us, or of an investment in us, may be significantly modified by future legislative or administrative changes or court decisions. Any modifications may or may not be retroactively applied.

For the reasons described below, Baker Botts L.L.P. has not rendered an opinion with respect to the following federal income tax issues: (1) whether holders of Series A Preferred Units will be treated as partners that receive guaranteed payments for the use of capital on their units (please read “Tax Consequences of Unit Ownership—Limited Partner Status”); (2) the treatment of a holder whose units are the subject of a securities loan (e.g., a loan to a short seller to cover a short sale of units) (please read “—Tax Consequences of Unit Ownership—Treatment of Short Sales”); and (3) whether distributions with respect to the Series A Preferred Units will be treated as unrelated business taxable income (please read “—Tax-Exempt Organizations and Other Investors”).

Taxation of the Partnership

Partnership Status

We expect to be treated as a partnership for federal income tax purposes and, therefore, subject to the discussion below under “—Administrative Matters—Information Returns and Audit Procedures,” generally will not be liable for entity-level federal income taxes. Instead, as described below, each of our common unitholders will take into account its respective share of our items of income, gain, loss and deduction in computing its federal income tax liability as if the unitholder had earned such income directly, even if we make no cash distributions to the unitholder. However, holders of Series A Preferred Units generally will not share in allocations of income, gain, loss or deduction. Please read “—Allocation of Income, Gain, Loss and Deduction.” Instead, we will treat distributions on preferred units as a guaranteed payment for the use of capital. Please read “—Treatment of Distributions on Series A Preferred Units.”

Section 7704 of the Code provides that publicly traded limited partnerships will, as a general rule, be taxed as corporations. However, an exception, referred to as the “Qualifying Income Exception,” exists with respect to publicly traded limited partnerships of which 90% or more of the gross income for every taxable year consists of “qualifying income.” Qualifying income includes income and gains derived from the transportation, processing, storage and marketing of crude oil, natural gas and refined products thereof. Other types of qualifying income include interest (other than from a financial business), dividends, gains from the sale of real property and gains from the sale or other disposition of capital assets held for the production of income that otherwise constitutes qualifying income. We estimate that less than 5% of our current gross income is not qualifying income; however, this estimate could change from time to time. Based upon and subject to this estimate, the factual representations made by us and our general partner and a review of the applicable legal authorities, Baker Botts L.L.P. is of the opinion that at least 90% of our current gross income constitutes qualifying income. The portion of our income that is qualifying income may change from time to time.

The IRS has made no determination as to our status or the status of our operating subsidiaries for federal income tax purposes. Instead, we will rely on the opinion of Baker Botts L.L.P. on such matters. It is the opinion of Baker Botts L.L.P. that, based upon the Code, its regulations, published revenue rulings and court decisions and the representations described below that:

S-40

In rendering its opinion, Baker Botts L.L.P. has relied on factual representations made by us and our general partner. The representations made by us and our general partner upon which Baker Botts L.L.P. has relied include:

We believe these representations are true and expect that these representations will continue to be true in the future.

The present federal income tax treatment of publicly traded partnerships or an investment in the units of publicly traded partnerships may be modified by administrative, legislative or judicial interpretation at any time. For example, from time to time, the President and members of the U.S. Congress propose and consider substantive changes to the existing federal income tax laws that affect publicly traded partnerships, such as proposals eliminating the Qualifying Income Exception upon which we rely for our treatment as a partnership for U.S. federal income tax purposes.

In addition, on January 24, 2017, the IRS and the U.S. Treasury Department published in the Federal Register final regulations regarding qualifying income under Section 7704(d)(1)(E) (the “Final Regulations”). The Final Regulations apply to taxable years beginning after January 19, 2017. Under current law and the Final Regulations, we believe that we satisfy the qualifying income requirement for us to be treated as a partnership for U.S. federal income tax purposes. However, there are no assurances that current law or the Final Regulations will not be revised to take a position that is contrary to our interpretation.

If we fail to meet the Qualifying Income Exception, other than a failure that is determined by the IRS to be inadvertent and that is cured within a reasonable time after discovery (in which case the IRS may also require us to make adjustments with respect to our unitholders or pay other amounts), we will be treated as if we had transferred all of our assets, subject to liabilities, to a newly formed corporation, on the first day of the year in which we fail to meet the Qualifying Income Exception, in return for stock in that corporation, and then distributed that stock to the unitholders in liquidation of their interests in us. This deemed contribution and liquidation should be tax-free to unitholders and us so long as we, at that time, do not have liabilities in excess of the tax basis of our assets. Thereafter, we would be treated as a corporation for federal income tax purposes.

If we were treated as an association taxable as a corporation in any taxable year, either as a result of a failure to meet the Qualifying Income Exception or otherwise, our items of income, gain, loss and deduction would be reflected only on our tax return rather than being passed through to our unitholders, and our net income would be taxed to us at corporate rates. In addition, any distribution made to a unitholder would be treated as taxable dividend income, to the extent of our current and accumulated earnings and profits, or, in the absence of earnings and profits, a nontaxable return of capital, to the extent of the unitholder’s tax basis in his units, or taxable capital gain, after the unitholder’s tax basis in his units is reduced to zero. Accordingly, taxation as a corporation would result in a material reduction in a unitholder’s cash flow and after-tax return and thus would likely result in a substantial reduction of the value of the units.

The discussion below is based on Baker Botts L.L.P.’s opinion that we will be classified as a partnership for federal income tax purposes.

S-41

Tax Consequences of Unit Ownership

Limited Partner Status

The tax treatment of our Series A Preferred Units is uncertain because there is no direct controlling authority with respect to interests such as the Series A Preferred Units. As such, Baker Botts L.L.P. is unable to opine as to the tax treatment of our Series A Preferred Units. Although the IRS may disagree with this treatment, we will treat our Series A Preferred Units as partnership interests and the holders of our Series A Preferred Units as partners entitled to a guaranteed payment for the use of capital on their units. If the Series A Preferred Units are not partnership interests, they would likely constitute indebtedness for federal income tax purposes and distributions on the Series A Preferred Units would constitute interest income to the holders of Series A Preferred Units. The remainder of this discussion assumes that our Series A Preferred Units are partnership interests for federal income tax purposes.

For a discussion related to the risks of losing partner status as a result of securities loans, please read “—Tax Consequences of Unit Ownership—Treatment of Short Sales.” Holders who are not treated as partners of the partnership as described above are urged to consult their own tax advisors with respect to the tax consequences applicable to them under their particular circumstances.

Treatment of Distributions on Series A Preferred Units

Subject to the discussion below under “—Entity-Level Collections of Unitholder Taxes” and “—Administrative Matters—Information Returns and Audit Procedures,” with respect to payments we may be required to make on behalf of our unitholders, we will not pay any federal income tax.

We will treat distributions to holders of Series A Preferred Units as guaranteed payments for the use of capital. Guaranteed payments accrued within the Partnership’s taxable year will be included as income to the holders of the Series A Preferred Units in such taxable year, whether or not a distribution of such payment has actually been made. We expect to make distributions to the holders of Series A Preferred Units semi-annually on                  and                  during the Fixed-Rate Period, and quarterly on                 ,                 ,                  and                  during the Floating-Rate Period, and the income related to such distributions will generally accrue to the holders of Series A Preferred Units on the record date for such distribution. Because the guaranteed payment for each unit must accrue as income to a holder during the taxable year of the accrual, the guaranteed payment attributable to the period beginning                  and ending December 31st will accrue to the holder of record of a Series A Preferred Unit on December 31st for such period. If you are a taxpayer reporting your income using the accrual method or using a taxable year other than the calendar year, you should consult your tax advisor with respect to the consequences of our guaranteed payment distribution accrual and reporting convention.

Although the IRS may disagree with this treatment, we will treat distributions on the Series A Preferred Units as guaranteed payments for the use of capital that will generally be taxable to the holders of Series A Preferred Units as ordinary income and will be deductible by us. Although a holder of Series A Preferred Units may recognize taxable income from the accrual of such a guaranteed payment even in the absence of a contemporaneous distribution, We anticipate accruing and making the guaranteed payment distributions semi-annually during the Fixed-Rate Period, and quarterly during the Floating-Rate Period as discussed above. Otherwise, the holders of Series A Preferred Units are generally not anticipated to share in our items of income, gain, loss or deduction, except to the extent necessary, to the extent possible, to provide the Series A Preferred Units with the benefit of the liquidation preference (please read “—Allocation of Income, Gain, Loss and Deduction” below). We will not allocate any share of our nonrecourse liabilities to the holders of Series A Preferred Units.

S-42

If the distributions to the Series A Preferred Units are not respected as guaranteed payments for the use of capital, holders of Series A Preferred Units may be treated as receiving an allocable share of gross income from the Partnership equal to their cash distributions, to the extent the Partnership has sufficient gross income to make such allocations of gross income. In the event there is not sufficient gross income to match such distributions, the distributions to the Series A Preferred Units would reduce the capital accounts of the Series A Preferred Units, requiring a subsequent allocation of income or gain to provide the Series A Preferred Units with their liquidation preference, if possible.

Basis of Units

A partner’s tax basis in its units (including Series A Preferred Units) initially will be the amount paid for those units.

Generally, if the distributions to the Series A Preferred Units are respected as a guaranteed payment for the use of capital, and subject to the discussion under “—Allocation of Income, Gain, Loss and Deduction,” a holder’s basis in its Series A Preferred Units will not be affected by distributions on such units. We do not anticipate that a holder of Series A Preferred Units will be allocated any share of our liabilities. The IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all of those interests. If you own common units and Series A Preferred Units, please consult your tax advisor with respect to determining the consequences of a guaranteed payment on your basis in your units.

Limitations on Deductibility of Losses

A holder of Series A Preferred Units will only be allocated loss to the extent the capital accounts of the common unitholders have been reduced to zero. Although it is not anticipated that a holder of Series A Preferred Units would be allocated loss, the deductibility of any such losses may be limited for various reasons. In addition, if you own other interests in the Partnership which may be allocated loss, the deductibility of such losses is also generally subject to limitations (including the passive loss limitations). We expect the guaranteed payment to be treated as “portfolio income” under the passive loss rules that may not generally be offset by any passive losses allocated in respect of such other interests in the Partnership. For a discussion of the passive loss rules and their applicability to holders of interests in the Partnership other than Series A Preferred Units, please read “Limitations on Deductibility of Losses” in the accompanying base prospectus. In the event that you are allocated loss as a holder of a Series A Preferred Unit or any other interest in us, please consult your tax advisor as to the application of any limitation to the deductibility of that loss.

Entity-Level Collections of Unitholder Taxes

If we are required or elect under applicable law to pay any federal, state, local or non-U.S. tax on behalf of any current or former unitholder or our general partner, our partnership agreement authorizes us to treat the payment as a distribution of cash to the relevant unitholder or general partner. Where the tax is payable on behalf of all unitholders or we cannot determine the specific unitholder on whose behalf the tax is payable, our partnership agreement authorizes us to treat the payment as a distribution to all current unitholders. Payments by us as described above could give rise to an overpayment of tax on behalf of a unitholder, in which event the unitholder may be entitled to claim a refund of the overpayment amount. Please read “—Administrative Matters—Information Returns and Audit Procedures”. Each unitholder is urged to consult its tax advisor to determine the consequences to them of any tax payment we make on its behalf.

Allocation of Income, Gain, Loss and Deduction

In general, if we have a net profit, our items of income, gain, loss and deduction will generally be allocated among our holders of units other than Series A Preferred Units in accordance with their percentage

S-43

interests in us. If we have a net loss, our items of income, gain, loss and deduction will generally be allocated among all of our common unitholders in accordance with their percentage interests in us to the extent of their positive capital accounts. If the capital accounts of the common unitholders have been reduced to zero, losses will be allocated to the Series A Preferred Units until the capital accounts of the Series A Preferred Units are reduced to zero. If Series A Preferred Units are allocated losses in any taxable period, gross income from a subsequent taxable period, if any, would be allocated to the Series A Preferred Units in a manner designed to provide their liquidation preferences.

Generally, holders of Series A Preferred Units will have a capital account equal to the liquidation preference of each Series A Preferred Unit, or $            , without regard to the price paid for such units, but will have an initial tax basis with respect to the Series A Preferred Units equal to the price paid for such units. To the extent the purchase price paid for a Series A Preferred Unit exceeds the liquidation preference of such unit, we will have income that will be allocated to our common unitholders in accordance with their percentage interest.

Treatment of Short Sales

A unitholder whose units are loaned to a “short seller” to cover a short sale of units may be considered as having disposed of those units. If so, he would no longer be treated for tax purposes as a partner with respect to those units during the period of the loan and may recognize gain or loss from the disposition. As a result, during this period:

Because there is no direct or indirect controlling authority on the issue relating to partnership interests, Baker Botts L.L.P. has not rendered an opinion regarding the tax treatment of a unitholder whose units are loaned to a short seller to cover a short sale of units; therefore, unitholders desiring to assure their status as partners and avoid the risk of gain recognition from a loan to a short seller are urged to consult a tax advisor to discuss whether it is advisable to modify any applicable brokerage account agreements to prohibit their brokers from borrowing and loaning their units. The IRS has previously announced that it is studying issues relating to the tax treatment of short sales of partnership interests. Please read “—Disposition of Units—Recognition of Gain or Loss.”

Tax Rates

Under current law, the highest marginal federal income tax rates for individuals applicable to ordinary income and long-term capital gains (generally, gains from the sale or exchange of certain investment assets held for more than one year) are 39.6% and 20%, respectively. These rates are subject to change by new legislation at any time.

In addition, a 3.8% Medicare tax or, NIIT applies to certain net investment income earned by individuals, estates, and trusts. For these purposes, net investment income generally includes guaranteed payments, a unitholder’s allocable share of our income, and gain realized by a unitholder from a sale of units. In the case of an individual, the tax will be imposed on the lesser of (i) the unitholder’s net investment income from all investments, or (ii) the amount by which the unitholder’s modified adjusted gross income exceeds $250,000 (if the unitholder is married and filing jointly or a surviving spouse), $125,000 (if married filing separately) or $200,000 (if the unitholder is unmarried or in any other case). In the case of an estate or trust, the tax will be imposed on the lesser of (i) undistributed net investment income, or (ii) the excess adjusted gross income over the dollar amount at which the highest income tax bracket applicable to an estate or trust begins.

S-44

Tax Treatment of Operations

Accounting Method and Taxable Year

We use the year ending December 31 as our taxable year and the accrual method of accounting for federal income tax purposes. Each holder of Series A Preferred Units will be required to include in its tax return its income from our guaranteed payments for each taxable year ending within or with its taxable year. A holder of Series A Preferred Units that has a taxable year ending on a date other than December 31 and that disposes of all its units following the close of our taxable year but before the close of its taxable year will be required to include in income for its taxable year its income from more than one year of guaranteed payments.

Disposition of Units

Recognition of Gain or Loss

A holder of Series A Preferred Units will be required to recognize gain or loss on a sale of such units equal to the difference between the holder’s amount realized and tax basis in the units sold. A holder’s amount realized generally will equal the sum of the cash and the fair market value of other property it receives for the unit. Gain or loss recognized by a holder on the sale or exchange of a unit held for more than one year generally will be taxable as long-term capital gain or loss. Net capital loss may offset capital gains and, in the case of individuals, up to $3,000 of ordinary income per year.

Furthermore, as described above, the IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all of those interests (presumably including both common units and Series A Preferred Units). Upon a sale or other disposition of less than all of those interests, a portion of that tax basis must be allocated to the interests sold using an “equitable apportionment” method, which generally means that the tax basis allocated to the interest sold equals an amount that bears the same relation to the partner’s tax basis in its entire interest in the partnership as the value of the interest sold bears to the value of the partner’s entire interest in the partnership.

Treasury Regulations under Section 1223 of the Code allow a selling partner who can identify units transferred with an ascertainable holding period to elect to use the actual holding period of the units transferred. Thus, according to the ruling discussed in the paragraph above, a partner will be unable to select high or low basis units to sell as would be the case with corporate stock, but, according to the Treasury Regulations, it may designate specific units sold for purposes of determining the holding period of the units transferred. A partner electing to use the actual holding period of units transferred must consistently use that identification method for all subsequent sales or exchanges of our units. A partner considering the purchase of additional units or a sale of units purchased in separate transactions is urged to consult its tax advisor as to the possible consequences of this ruling and application of the Treasury Regulations.

Specific provisions of the Code affect the taxation of some financial products and securities, including partnership interests, by treating a taxpayer as having sold an “appreciated” financial position, including a partnership interest with respect to which gain would be recognized if it were sold, assigned or terminated at its fair market value, in the event the taxpayer or a related person enters into:

S-45

Moreover, if a taxpayer has previously entered into a short sale, an offsetting notional principal contract or a futures or forward contract with respect to the partnership interest, the taxpayer will be treated as having sold that position if the taxpayer or a related person then acquires the partnership interest or substantially identical property. The Secretary of the Treasury is authorized to issue Treasury Regulations that treat a taxpayer that enters into transactions or positions that have substantially the same effect as the preceding transactions as having constructively sold the financial position.

Recognition of Gain or Loss on Redemption

The receipt by a unitholder of amounts in redemption of their Series A Preferred Units generally will result in the recognition of taxable gain to the unitholder for federal income tax purposes only if and to the extent the amount of redemption proceeds received exceeds their tax basis in all the units (including common units and Series A Preferred Units) held by the unitholder immediately before the redemption. Any such redemption of Series A Preferred Units would result in the recognition of taxable loss to the holder for federal income tax purposes only if the holder does not hold any other units (including common units and Series A Preferred Units) immediately after the redemption and the unitholder’s tax basis in the redeemed Series A Preferred Units exceeds the amounts received by the unitholder in redemption thereof. Any taxable gain or loss recognized under the foregoing rules would be treated in the same manner as taxable gain or loss recognized on a sale of Series A Preferred Units as described above in “Disposition of Units—Recognition of Gain or Loss on Sale.”

Allocations Between Transferors and Transferees

Holders of Series A Preferred Units owning Series A Preferred Units as of the close of the business on the first Business Day of the month of the applicable Distribution Payment Date (the “Record Date”) will generally be entitled to receive the distribution of the guaranteed payment payable with respect to their units for the applicable semi-annual or quarterly period on the next Distribution Payment Date. Purchasers of Series A Preferred Units after the Record Date will therefore not be entitled to a cash distribution on their Series A Preferred Units until the next Distribution Payment Date.

Notification Requirements

A unitholder who sells or exchanges any of its units is generally required to notify us in writing of that transaction within 30 days after the transaction (or, if earlier, January 15 of the year following the transaction in the case of a seller). A purchaser of Series A Preferred Units who purchases Series A Preferred Units from another unitholder is also generally required to notify us in writing of that purchase within 30 days after the purchase. Upon receiving such notifications, we are required to notify the IRS of that transaction and to furnish specified information to the transferor and transferee. Failure to notify us of a transfer of units may, in some cases, lead to the imposition of penalties. However, these reporting requirements do not apply to a sale by an individual who is a citizen of the United States and who effects the sale or exchange through a broker who will satisfy such requirements.

Constructive Termination

We will be considered to have technically terminated our partnership for federal income tax purposes upon the sale or exchange of 50% or more of the total interests in our capital and profits within a twelve-month period. For purposes of measuring whether the 50% threshold is reached, multiple sales of the same unit are counted only once. A technical termination results in the closing of our taxable year for all unitholders. In the case of a unitholder reporting on a taxable year other than the calendar year, the closing of our taxable year may result in more than twelve months of our taxable income or loss being includable in such unitholder’s taxable income for the year of termination.

A technical termination occurring on a date other than December 31 would require that we file two tax returns for one fiscal year, thereby increasing our administration and tax preparation costs. However, pursuant to an IRS relief procedure the IRS may allow a technically terminated partnership to provide a single Schedule K-1

S-46

for the calendar year in which a termination occurs. Following a technical termination, we would be required to make new tax elections, including a new election under Section 754 of the Code, and the termination would result in a deferral of our deductions for depreciation and thus may increase the taxable income allocable to our unitholders. A technical termination could also result in penalties if we were unable to determine that the technical termination had occurred. Moreover, a technical termination may either accelerate the application of, or subject us to, any tax legislation enacted before the technical termination that would not otherwise have been applied to us as a continuing partnership as opposed to a terminating partnership.

Tax-Exempt Organizations and Other Investors

Ownership of units by employee benefit plans and other tax-exempt organizations as well as by non-resident alien individuals, non-U.S. corporations and other non-U.S. persons (collectively, “Non-U.S. Holders”) raises issues unique to those investors and, as described below, may have substantially adverse tax consequences to them. Prospective holders that are tax-exempt entities or Non-U.S. Holders should consult their tax advisors before investing in our units. Employee benefit plans and most other tax-exempt organizations, including IRAs and other retirement plans, are subject to federal income tax on unrelated business taxable income, or UBTI. Virtually all of our income will be unrelated business taxable income and will be taxable to a tax-exempt holder.

We will treat distributions on the Series A Preferred Units as guaranteed payments for the use of capital. The treatment of guaranteed payments for the use of capital to tax-exempt investors is not certain because there is no direct controlling authority on such treatment. Such payments may be treated as UBTI for federal income tax purposes and Baker Botts L.L.P. is unable to opine with respect to whether such payments constitute UBTI for federal income tax purposes. If you are a tax-exempt entity, you should consult your tax advisor with respect to the consequences of owning our Series A Preferred Units.

Non-U.S. Unitholders are taxed by the United States on income effectively connected with a U.S. trade or business (“effectively connected income”) and on certain types of U.S.-source non-effectively connected income (such as dividends and guaranteed payments), unless exempted or further limited by an income tax treaty. Each Non-U.S. Unitholder will be considered to be engaged in business in the United States because of its ownership of our units. Furthermore, it is probable that Non-U.S. Unitholders will be deemed to conduct such activities through a permanent establishment in the United States within the meaning of any applicable tax treaty. Consequently, each Non-U.S. Unitholder will be required to file federal tax returns to report its share of our income, gain, loss or deduction (in the case of holders of common units) or their share of income from guaranteed payments (in the case of holders of Series A Preferred Units) and pay federal income tax on its share of our net income or gain. Moreover, under rules applicable to publicly-traded partnerships, distributions to Non-U.S. Unitholders are subject to withholding at the highest applicable effective tax rate. Each Non-U.S. Unitholder must obtain a taxpayer identification number from the IRS and submit that number to our transfer agent on a Form W-8BEN or W-8BEN-E (or other applicable or successor form) in order to obtain credit for these withholding taxes.

In addition, if a Non-U.S. Unitholder is classified as a non-U.S. corporation, it will be treated as engaged in a United States trade or business and may be subject to the U.S. branch profits tax at a rate of 30%, in addition to regular federal income tax, on its share of our income and gain as adjusted for changes in the foreign corporation’s “U.S. net equity” to the extent reflected in the corporation’s earnings and profits. That tax may be reduced or eliminated by an income tax treaty between the United States and the country in which the foreign corporate unitholder is a “qualified resident.” In addition, this type of unitholder is subject to special information reporting requirements under Section 6038C of the Code.

A Non-U.S. Unitholder who sells or otherwise disposes of a unit will be subject to federal income tax on gain realized from the sale or disposition of that unit to the extent the gain is effectively connected with a U.S. trade or business of the Non-U.S. Unitholder. Under a ruling published by the IRS interpreting the scope of

S-47

“effectively connected income,” gain realized by a Non-U.S. Unitholder from the sale of its interest in a partnership that is engaged in a trade or business in the United States will be considered to be “effectively connected” with a U.S. trade or business. Although one court that recently reviewed the IRS position rejected it as unpersuasive, part or all of a Non-U.S. Unitholder’s gain from the sale or other disposition of units may be treated as effectively connected with a unitholder’s indirect U.S. trade or business constituted by its investment in us.

Moreover, under the Foreign Investment in Real Property Tax Act, as long as our partnership units continue to be regularly traded on an established securities market, a Non-U.S. Unitholder generally will only be subject to federal income tax upon the sale or disposition of a unit if at any time during the shorter of the five-year period ending on the date of the disposition or the Non-U.S. Unitholder’s holding period for the unit (i) such Non-U.S. Unitholder owned (directly or indirectly constructively applying certain attribution rules) more than 5% of our units and (ii) 50% or more of the fair market value of our real property interests and other assets used or held for use in a trade or business consisted of U.S. real property interests (which include U.S. real estate, including land, improvements, and associated personal property, and interests in certain entities holding U.S. real estate). If our units were not considered to be regularly traded on an established securities market, such Non-U.S. Unitholder (regardless of the percentage of units owned) would be subject to federal income tax on a taxable disposition of our units, and a 15% withholding tax would apply to the gross proceeds from such disposition (as described in the preceding paragraph). Currently, more than 50% of our assets consist of U.S. real property interests and we do not expect that to change in the foreseeable future. Therefore, each Non-U.S. Unitholder may be subject to federal income tax on gain from the sale or disposition of its units.

Administrative Matters

Information Returns and Audit Procedures

We intend to furnish to each holder of Series A Preferred Units, within 90 days after the close of each taxable year, specific tax information, including a Schedule K-1, which describes its preferred return for the preceding taxable year. Notwithstanding the rules described above under “—Basis of Units” requiring aggregation of partnership interests purchased in separate transactions, you may receive two Schedules K-1 if you hold common units and Series A Preferred Units due to administrative reporting limitations.

In preparing this information, which will not be reviewed by counsel, we will take various accounting and reporting positions, some of which have been mentioned earlier, to determine each unitholder’s share of income, gain, loss and deduction. We cannot assure our unitholders that those positions will yield a result that conforms to all of the requirements of the Code, Treasury Regulations or administrative interpretations of the IRS.

The IRS may audit our federal income tax information returns. Neither we nor Baker Botts L.L.P. can assure prospective unitholders that the IRS will not successfully challenge the positions we adopt, and such a challenge could adversely affect the value of the units. Adjustments resulting from an IRS audit may require each unitholder to adjust a prior year’s tax liability, and may result in an audit of the unitholder’s own return. Any audit of a unitholder’s return could result in adjustments unrelated to our returns.

A publicly-traded partnership is treated as an entity separate from its owners for purposes of federal income tax audits, judicial review of administrative adjustments by the IRS and tax settlement proceedings. The tax treatment of partnership items of income, gain, loss and deduction are determined in a partnership proceeding rather than in separate proceedings of the partners. The Code requires that one partner be designated as the “Tax Matters Partner” for these purposes, and our partnership agreement designates our general partner.

The Tax Matters Partner can extend the statute of limitations for assessment of tax deficiencies against unitholders for items in our returns. The Tax Matters Partner may bind a unitholder with less than a 1% profits

S-48

interest in us to a settlement with the IRS unless that unitholder elects, by filing a statement with the IRS, not to give that authority to the Tax Matters Partner. The Tax Matters Partner may seek judicial review, by which all the unitholders are bound, of a final partnership administrative adjustment and, if the Tax Matters Partner fails to seek judicial review, judicial review may be sought by any unitholder having at least a 1% interest in profits or by any group of unitholders having in the aggregate at least a 5% interest in profits. However, only one action for judicial review may go forward, and each unitholder with an interest in the outcome may participate in that action.

A unitholder must file a statement with the IRS identifying the treatment of any item on its federal income tax return that is not consistent with the treatment of the item on our return. Intentional or negligent disregard of this consistency requirement may subject a unitholder to substantial penalties.

Pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, for taxable years beginning after December 31, 2017, if the IRS makes an audit adjustment to any of our income tax returns, it may assess and collect any taxes (including any applicable penalties and interest) resulting from such audit adjustment directly from us, unless we elect to have our general partner and unitholders take the audit adjustment into account in accordance with their interests in us during the taxable year under audit. Similarly, for such taxable years, if the IRS makes an audit adjustment to an income tax return filed by an entity in which we are a member or partner, it may assess and collect any taxes (including penalties and interest) resulting from such audit adjustment directly from such entity. Generally, we expect to elect to have our general partner and unitholders take any material audit adjustment into account in accordance with their interests in us during the taxable year under audit, but there can be no assurance that such election, if made, will be effective in all circumstances. With respect to an audit adjustment as to an entity in which we are a member or partner, we may not be able to have our general partner and our unitholders take such audit adjustment into account in accordance with their interests in us during the taxable year under audit, and if we are unable to do so, our then current unitholders may bear some or all of the tax liability resulting from such audit adjustment, even if such unitholders did not own our units during the taxable year under audit. If, as a result of any such audit adjustment, we are required to make payments of taxes, penalties, or interest, we may require our unitholders and former unitholders to reimburse us for such taxes (including any applicable penalties or interest) or, if we are required to bear such payment, our cash available for distribution to our unitholders might be substantially reduced.

Additionally, pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, the Code will no longer require that we designate a “tax matters partner” pursuant to Section 6231(a)(7) of the Code (prior to amendment by the Bipartisan Budget Act of 2015). Instead, for taxable years beginning after December 31, 2017, we will be required to designate a partner, or other person, with a substantial presence in the United States as our partnership representative (“Partnership Representative”). The Partnership Representative will have the sole authority to act on our behalf for purposes of, among other things, U.S. federal income tax audits and judicial review of administrative adjustments by the IRS. If we do not make such a designation, the IRS can select any person as the Partnership Representative. We currently anticipate that we will designate our general partner (or one of its affiliates) as the Partnership Representative. Further, any actions taken by us or by the Partnership Representative on our behalf with respect to, among other things, U.S. federal income tax audits and judicial review of administrative adjustments by the IRS, will be binding on us and all of the unitholders.

Nominee Reporting

Persons who hold an interest in us as a nominee for another person are required to furnish to us:

S-49

Each broker and financial institution is required to furnish additional information, including whether such broker or financial institution is a U.S. person and specific information on Series A Preferred Units such broker or financial institution acquires, holds or transfers for its own account. A penalty of $260 per failure, up to a maximum of $3,218,500 per calendar year, is imposed by the Code for failure to report that information to us. The nominee is required to supply the beneficial owner of the units with the information furnished to us.

Accuracy-Related Penalties

An additional tax equal to 20% of the amount of any portion of an underpayment of tax that is attributable to one or more specified causes, including negligence or disregard of rules or regulations, substantial understatements of income tax and substantial valuation misstatements, is imposed by the Code. No penalty will be imposed, however, for any portion of an underpayment if it is shown that there was a reasonable cause for that portion and that the taxpayer acted in good faith regarding that portion.

For individuals, a substantial understatement of income tax in any taxable year exists if the amount of the understatement exceeds the greater of 10% of the tax required to be shown on the return for the taxable year or $5,000 ($10,000 for most corporations). The amount of any understatement subject to penalty generally is reduced if any portion is attributable to a position adopted on the return:

If any item of income, gain, loss or deduction included in the distributive shares of unitholders might result in that kind of an “understatement” of income for which no “substantial authority” exists, we must disclose the pertinent facts on our return. In addition, we will make a reasonable effort to furnish sufficient information for unitholders to make adequate disclosure on their returns and to take other actions as may be appropriate to permit unitholders to avoid liability for this penalty. More stringent rules apply to “tax shelters,” which we do not believe includes us, or any of our investments, plans or arrangements.

A substantial valuation misstatement exists if (a) the value of any property, or the adjusted basis of any property, claimed on a tax return is 150% or more of the amount determined to be the correct amount of the valuation or adjusted basis, (b) the price for any property or services (or for the use of property) claimed on any such return with respect to any transaction between persons described in Code Section 482 is 200% or more (or 50% or less) of the amount determined under Section 482 to be the correct amount of such price, or (c) the net Code Section 482 transfer price adjustment for the taxable year exceeds the lesser of $5.0 million or 10% of the taxpayer’s gross receipts. No penalty is imposed unless the portion of the underpayment attributable to a substantial valuation misstatement exceeds $5,000 ($10,000 for most corporations). If the valuation claimed on a return is 200% or more than the correct valuation or certain other thresholds are met, the penalty imposed increases to 40%. We do not anticipate making any valuation misstatements.

S-50

In addition, the 20% accuracy-related penalty also applies to any portion of an underpayment of tax that is attributable to transactions lacking economic substance. To the extent that such transactions are not disclosed, the penalty imposed is increased to 40%. Additionally, there is no reasonable cause defense to the imposition of this penalty to such transactions.

Reportable Transactions

If we were to engage in a “reportable transaction,” we (and possibly you and others) would be required to make a detailed disclosure of the transaction to the IRS. A transaction may be a reportable transaction based upon any of several factors, including the fact that it is a type of tax avoidance transaction publicly identified by the IRS as a “listed transaction” or that it produces certain kinds of losses for partnerships, individuals, S corporations, and trusts in excess of $2.0 million in any single year, or $4.0 million in any combination of six successive tax years. Our participation in a reportable transaction could increase the likelihood that our federal income tax information return (and possibly your tax return) would be audited by the IRS. Please read “—Administrative Matters—Information Returns and Audit Procedures”.”

Moreover, if we were to participate in a reportable transaction with a significant purpose to avoid or evade tax, or in any listed transaction, you may be subject to the following additional consequences:

We do not believe that we have engaged, and do not expect to engage, in any “reportable transactions.”

State, Local, Foreign and Other Tax Considerations

In addition to federal income taxes, unitholders likely will be subject to other taxes, such as state, local and foreign income taxes, unincorporated business taxes, and estate, inheritance or intangible taxes that may be imposed by the various jurisdictions in which we do business or own property or in which you are a resident. We currently do business or own property in Colorado, North Dakota, Texas, Utah, Ohio, New Mexico, Wyoming and West Virginia. Several of these states impose a personal income tax on individuals and certain of these states also impose an income tax on corporations and other entities. Moreover, in the future we may also own property or do business in other states that impose income or similar taxes on non-resident individuals and corporations. Although an analysis of those various taxes is not presented here, each prospective unitholder should consider their potential impact on his investment in us. Although a unitholder may not be required to file a return and pay taxes in some jurisdictions if the unitholder’s income from that jurisdiction falls below the filing and payment requirement, a unitholder may be required to file income tax returns and to pay income taxes in other jurisdictions in which we do business or own property and may be subject to penalties for failure to comply with those requirements. In some jurisdictions, tax losses may not produce a tax benefit in the year incurred and may not be available to offset income in subsequent taxable years. Some of the jurisdictions may require us, or we may elect, to withhold a percentage of income from amounts to be distributed to a unitholder who is not a resident of the jurisdiction. Withholding, the amount of which may be greater or less than a particular unitholder’s income tax liability to the jurisdiction, generally does not relieve a nonresident unitholder from the obligation to file an income tax return. Amounts withheld will be treated as if distributed to unitholders for purposes of determining the amounts distributed by us. Please read “—Tax Consequences of Unit Ownership—Entity-Level Collections of Unitholder Taxes.” Based on current law and our estimate of our future operations, our general partner anticipates that any amounts required to be withheld will not be material.

S-51

It is the responsibility of each unitholder to investigate the legal and tax consequences, under the laws of pertinent states, localities and foreign jurisdictions, of his investment in us. Accordingly, each prospective unitholder is urged to consult his own tax counsel or other advisor with regard to those matters. Further, it is the responsibility of each unitholder to file all state, local and foreign, as well as U.S. federal tax returns, that may be required of him. Baker Botts L.L.P. has not rendered an opinion on the state, local or foreign tax consequences of an investment in us.

S-52

UNDERWRITING

Merrill Lynch, Pierce, Fenner & Smith Incorporated, Credit Suisse Securities (USA) LLC, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC, are acting as the joint book-running managers of this offering, and Merrill Lynch, Pierce, Fenner & Smith Incorporated is acting as representative of each of the underwriters named below. Subject to the terms and conditions set forth in an underwriting agreement among us and the underwriters, we have agreed to sell to the underwriters, and each of the underwriters has agreed, severally and not jointly, to purchase from us, the number of Series A Preferred Units set forth opposite its name below.

Subject to the terms and conditions set forth in the underwriting agreement, the underwriters have agreed, severally and not jointly, to purchase all of the Series A Preferred Units sold under the underwriting agreement if any of these Series A Preferred Units are purchased. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the nondefaulting underwriters may be increased or the underwriting agreement may be terminated.

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act or to contribute to payments the underwriters may be required to make in respect of those liabilities.

The underwriters are offering the Series A Preferred Units, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel, including the validity of the shares, and satisfaction of other conditions contained in the underwriting agreement, such as the receipt by the underwriters of officers’ certificates and legal opinions. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

Commissions and Discounts

The representative has advised us that the underwriters propose initially to offer the Series A Preferred Units to the public at the public offering price set forth on the cover page of this prospectus supplement and to dealers at that price less a concession not in excess of $         per Series A Preferred Unit. After the initial offering, the public offering price, concession or any other term of this offering may be changed.

The following table shows the public offering price, underwriting discount and proceeds, before expenses, to us.

S-53

The expenses of this offering, not including the underwriting discount, are estimated at approximately $1.25 million and are payable by us.

No Sales of Similar Securities

We have agreed that, for a period of 30 days after the date of this prospectus supplement and subject to certain exceptions, we will not, directly or indirectly, without the prior written consent of the representative, (i) offer for sale, sell, pledge, or otherwise dispose of (or enter into any transaction or device that is designed to, or could be expected to, result in the disposition by any person at any time in the future of) any Series A Preferred Units or securities convertible into or exercisable or exchangeable for Series A Preferred Units, or sell or grant options, rights or warrants with respect to any Series A Preferred Units or securities convertible into or exercisable or exchangeable for Series A Preferred Units, or, in either case, any securities that are substantially similar to the Series A Preferred Units, (ii) enter into any swap or other derivatives transaction that transfers to another, in whole or in part, any of the economic benefits or risks of ownership of such Series A Preferred Units, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Series A Preferred Units or other securities, in cash or otherwise, (iii) file or cause to be filed a registration statement, including any amendments thereto, with respect to the registration of any Series A Preferred Units or securities convertible, exercisable or exchangeable into Series A Preferred Units or other securities of the Partnership or (iv) publicly disclose the intention to do any of the foregoing.

No Listing

The Series A Preferred Units are a new issue of securities with no established trading market and we do not intend to list the Series A Preferred Units on any securities exchange. Accordingly, an active trading market for the Series A Preferred Units may not develop or, even if one develops, may not last, in which case the liquidity and market price of the Series A Preferred Units could be adversely affected, the difference between bid and asked prices could be substantial and your ability to transfer Series A Preferred Units at the time and price desired will be limited.

Price Stabilization, Short Positions

Until the distribution of the Series A Preferred Units is completed, SEC rules may limit underwriters and selling group members from bidding for and purchasing our Series A Preferred Units. However, the representative may engage in transactions that have the effect of stabilizing the price of the Series A Preferred Units, such as purchases and other activities that peg, fix or maintain that price.

In connection with this offering, the underwriters may bid for or purchase and sell our Series A Preferred Units in the open market. These transactions may include short sales and purchases on the open market to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater number of Series A Preferred Units than they are required to purchase in this offering. The underwriters may close out any short position by purchasing Series A Preferred Units in the open market.

Similar to other purchase transactions, the underwriters’ purchases to cover the syndicate short sales and other activities may have the effect of raising or maintaining the market price of our Series A Preferred Units or preventing or retarding a decline in the market price of our Series A Preferred Units. As a result, the price of our Series A Preferred Units may be higher than the price that might otherwise exist in the open market. The underwriters may conduct these transactions in the over-the-counter market or otherwise.

Neither we nor any of the underwriters make any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of our Series A Preferred Units. In addition, neither we nor any of the underwriters make any representation that the representative will engage in these transactions or that these transactions, once commenced, will not be discontinued without notice.

S-54

Extended Settlement

We expect that delivery of the Series A Preferred Units will be made to investors on or about             , 2017, which will be the third business day following the date of this prospectus supplement (such settlement being referred to as “T+3”). Under Rule 15c6-1 under the Exchange Act, trades in the secondary market are required to settle in two business days, unless the parties to any such trade expressly agree otherwise. Purchasers who wish to trade Series A Preferred Units on any date prior to the business day before delivery will be required, by virtue of the fact that the Series A Preferred Units initially settle in T+3, to specify an alternate settlement arrangement at the time of any such trade to prevent a failed settlement. Purchasers of the Series A Preferred Units who wish to trade the Series A Preferred Units on any date prior to the business day before delivery should consult their advisors.

Electronic Distribution

In connection with this offering, certain of the underwriters or securities dealers may distribute prospectuses by electronic means, such as e-mail.

Other Relationships

Some of the underwriters and their affiliates have engaged in, and may in the future engage in, investment banking and other commercial dealings in the ordinary course of business with us or our affiliates. They have received, or may in the future receive, customary fees and commissions for these transactions. Affiliates of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Credit Suisse Securities (USA) LLC, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are lenders under our revolving credit facility that we expect to reduce using the net proceeds from this offering and, accordingly, such underwriters will receive a portion of the net proceeds from this offering.

In addition, in the ordinary course of their business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. Certain of the underwriters or their affiliates that have a lending relationship with us routinely hedge their credit exposure to us consistent with their customary risk management policies. Typically, such underwriters and their affiliates would hedge such exposure by entering into transactions that consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the Series A Preferred Units. Any such short positions could adversely affect future trading prices of our Series A Preferred Units. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

FINRA

Because the Financial Industry Regulatory Authority, Inc. (“FINRA”) views the Series A Preferred Units offered hereby as interests in a direct participation program, the offering is being made in compliance with Rule 2310 of the FINRA Rules. Investor suitability with respect to the Series A Preferred Units will be judged similarly to the suitability with respect to other securities that are listed for trading on a national securities exchange.

S-55

LEGAL MATTERS

The validity of the Series A Preferred Units being offered in this prospectus supplement will be passed upon for us by Baker Botts L.L.P., Houston, Texas. Certain legal matters will be passed upon for the underwriters by Vinson  & Elkins L.L.P., Houston, Texas.

EXPERTS

The consolidated financial statements of Summit Midstream Partners, LP and subsidiaries incorporated in this prospectus supplement by reference from Summit Midstream Partners, LP’s Current Report on Form 8-K, as filed with the SEC on November 6, 2017, and the effectiveness of Summit Midstream Partners, LP’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of Ohio Gathering Company, L.L.C. as of and for the years ended December 31, 2015 and 2014 incorporated in this prospectus supplement by reference to Exhibit 99.3 from Summit Midstream Partners, LP’s Annual Report on Form 10-K for the year ended December 31, 2016 have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of Ohio Condensate Company, L.L.C. as of and for the years ended December 31, 2015 and 2014 incorporated in this prospectus supplement by reference to Exhibit 99.4 from Summit Midstream Partners, LP’s Annual Report on Form 10-K for the year ended December 31, 2016 have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of Ohio Gathering Company, L.L.C. incorporated in this prospectus supplement by reference to Exhibit 99.1 in the Summit Midstream Partners, LP Annual Report on Form 10-K for the year ended December 31, 2016 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

The financial statements of Ohio Condensate Company, L.L.C. incorporated in this prospectus supplement by reference to Exhibit 99.2 in the Summit Midstream Partners, LP Annual Report on Form 10-K for the year ended December 31, 2016 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

We have filed a registration statement with the SEC under the Securities Act of 1933, as amended, that registers the offer and sale from time to time of our common units, preferred units and debt securities, including the Series A Preferred Units covered by this prospectus supplement. The registration statement, including the attached exhibits, contains additional relevant information about us and our securities. In addition, we file annual, quarterly and current reports with the SEC. Our SEC filings are available over the internet at the SEC’s website at www.sec.gov. You also can read and copy any document we file at the SEC’s public reference room at 100F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for more information on the public reference room and its copy charges. You also can obtain information about us at the offices of the New York Stock Exchange, 20 Broad Street, New York, New York 10005.

S-56

We also make available free of charge on our internet website at www.summitmidstream.com our annual reports on Form 10-K, our quarterly reports on Form 10-Q, our current reports on Form 8-K and any amendments to those reports, as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Information contained on our website is not incorporated reference into this prospectus supplement or the accompanying base prospectus and you should not consider information contained on our website as part of this prospectus supplement or the accompanying base prospectus.

S-57

INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” the information we have filed with the SEC. This means that we can disclose important information to you without actually including the specific information in this prospectus supplement or the accompanying base prospectus by referring you to other documents filed separately with the SEC. The information incorporated by reference in this prospectus supplement and the accompanying base prospectus is an important part hereof and thereof. Information that we later provide to the SEC, and that is deemed to be “filed” with the SEC, will automatically update information previously filed with the SEC and may replace information in this prospectus supplement and the accompanying base prospectus and information previously filed with the SEC.

We incorporate by reference in this prospectus supplement the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (excluding information deemed to be furnished and not filed with the SEC):

You may request a copy of any document incorporated by reference in this prospectus supplement or the accompanying base prospectus and any exhibit specifically incorporated by reference in those documents, at no cost, by writing or telephoning us at the following address or phone number:

Summit Midstream Partners, LP

1790 Hughes Landing Boulevard, Suite 500

The Woodlands, Texas 77380

Attention: Brock M. Degeyter

Executive Vice President, General Counsel

and Chief Compliance Officer

Telephone: (832) 413-4770

S-58

FORWARD-LOOKING STATEMENTS

Investors are cautioned that certain statements contained in or incorporated by reference in this prospectus supplement as well as in periodic press releases and certain oral statements made by our officials during our presentations are “forward-looking” statements. Forward-looking statements include, without limitation, any statement that may project, indicate or imply future results, events, performance or achievements, and may contain the words “expect,” “intend,” “plan,” “anticipate,” “estimate,” “believe,” “will be,” “will continue,” “will likely result” and similar expressions, or future conditional verbs such as “may,” “will,” “should,” “would” and “could.” In addition, any statement concerning future financial performance (including future revenues, earnings or growth rates), ongoing business strategies or prospects, and possible actions taken by us, our subsidiaries, Summit Midstream Partners, LLC or our Sponsor, are also forward-looking statements. These forward-looking statements involve various risks and uncertainties, including, but not limited to, those described under the section entitled “Risk Factors” included herein.

Forward-looking statements are based on current expectations and projections about future events and are inherently subject to a variety of risks and uncertainties, many of which are beyond the control of our management team. All forward-looking statements in this prospectus supplement and subsequent written and oral forward-looking statements attributable to us, or to persons acting on our behalf, are expressly qualified in their entirety by the cautionary statements in this paragraph. These risks and uncertainties include, among others:

S-59

Developments in any of these areas could cause actual results to differ materially from those anticipated or projected or cause a significant reduction in the market price of our common units, preferred units and senior notes.

The foregoing list of risks and uncertainties may not contain all of the risks and uncertainties that could affect us. In addition, in light of these risks and uncertainties, the matters referred to in the forward-looking statements contained or incorporated by reference in this prospectus may not in fact occur. Accordingly, undue reliance should not be placed on these statements. We undertake no obligation to publicly update or revise any forward-looking statements as a result of new information, future events or otherwise, except as otherwise required by law.

S-60

PROSPECTUS

Summit Midstream Partners, LP

Summit Midstream Holdings, LLC

Summit Midstream Finance Corp.

Common Units Representing Limited Partner Interests

Preferred Units Representing Limited Partner Interests

Debt Securities

Summit Midstream Partners, LP (the “Partnership,” “we,” “our” or “us”) may from time to time, in one or more offerings, offer and sell common units representing limited partner interests in the Partnership (the “common units”) or preferred units representing limited partner interests in the Partnership (the “preferred units”). We or Summit Midstream Holdings, LLC, together with Summit Midstream Finance Corp., may offer and sell debt securities described in this prospectus. Summit Midstream Finance Corp. may act as co-issuer of the debt securities, and certain direct or indirect subsidiaries of the Partnership or Summit Midstream Holdings, LLC may guarantee any debt securities offered by this prospectus, if and to the extent identified in the related prospectus supplement. We refer to the common units, preferred units, debt securities and any related guarantees collectively as the “securities.”

We may offer and sell these securities in amounts, at prices and on terms to be determined by market conditions and other factors at the time of our offerings. We may offer and sell these securities to or through one or more underwriters on a continuous or delayed basis. This prospectus describes only the general terms of the securities and the general manner in which we will offer the securities. The specific terms of any securities we offer will be included in a supplement to this prospectus. The prospectus supplement will describe the specific manner in which we will offer the securities and also may add, update or change information contained in this prospectus. The names of any underwriters and the specific terms of a plan of distribution will be stated in the prospectus supplement.

Our common units are traded on the New York Stock Exchange (“NYSE”) under the symbol “SMLP.” We will provide information in the related prospectus supplement for the trading market, if any, for any preferred units or debt securities that may be offered.

Investing in our securities involves a high degree of risk. Limited partnerships are inherently different from corporations. You should review carefully the risk factors described under “Risk Factors” beginning on page 3 of this prospectus for a discussion of important risks you should consider before you make an investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is November 6, 2017

Table of Contents

Neither we nor any underwriter has authorized anyone to provide you with any information or to make any representations other than those contained or incorporated by reference in this prospectus or any prospectus supplement. If anyone provides you with additional, different or inconsistent information, you should not rely on it. You should not assume that the information in this prospectus or any prospectus supplement or free writing prospectus is accurate as of any date other than the date on the cover page of this prospectus or that any information we have incorporated by reference is accurate as of any date other than the date of the documents incorporated by reference. Our business, financial condition, results of operations and prospects may have changed since such dates. We will only offer to sell, and seek offers to buy, the securities registered under this prospectus in jurisdictions where such offers and sales are permitted.

i

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we have filed with the Securities and Exchange Commission (the “SEC”) using a “shelf” registration process. Under this shelf registration process, we may over time, in one or more offerings, offer and sell any combination of the securities described in this prospectus.

This prospectus provides you with a general description of Summit Midstream Partners, LP and the securities that are registered hereunder. Each time we or Summit Midstream Holdings, LLC, together with Summit Midstream Finance Corp., sell any securities offered by this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering and the securities being offered. Any prospectus supplement may also add to, update or change information contained in this prospectus. To the extent information in this prospectus is inconsistent with the information contained in a prospectus supplement, you should rely on the information in the prospectus supplement.

Additional information, including our financial statements and the notes thereto, is incorporated in this prospectus by reference to our reports filed with the SEC. Before you invest in our securities, you should carefully read this prospectus, including the information provided under the heading “Risk Factors,” any prospectus supplement, the information incorporated by reference in this prospectus and any prospectus supplement (including the documents described under the heading “Where You Can Find More Information” in both this prospectus and any prospectus supplement), and any additional information you may need to make your investment decision.

ii

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly, current and other reports with the SEC under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) (File No. 001-35666). You may read and copy any document we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information about the public reference room. Our SEC filings are also available to the public through the SEC’s website at www.sec.gov. You can also obtain information about us at the offices of the NYSE, 20 Broad Street, New York, New York 10005.

Our internet address is www.summitmidstream.com. Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings with the SEC are available, free of charge, through our website, as soon as reasonably practicable after those reports or filings are electronically filed with or furnished to the SEC. Information on our website or any other website is not incorporated by reference into this prospectus and you should not consider information contained on our website as part of this prospectus.

We “incorporate by reference” information into this prospectus, which means that we disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus, except for any information superseded by information contained expressly in this prospectus. You should not assume that the information in this prospectus is current as of the date other than the date on the cover page of this prospectus.

We incorporate by reference in this prospectus the documents listed below and any subsequent filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (excluding information deemed to be furnished and not filed with the SEC) until all offerings under the registration statement of which this prospectus forms a part are completed or terminated:

You may request a copy of any document incorporated by reference in this prospectus and any exhibit specifically incorporated by reference in those documents, at no cost, by writing or telephoning us at the following address or phone number:

Summit Midstream Partners, LP

1790 Hughes Landing Blvd, Suite 500

The Woodlands, Texas 77380

Attention: Brock M. Degeyter

Executive Vice President, General Counsel and

Chief Compliance Officer

Telephone: (832) 413-4770

iii

FORWARD-LOOKING STATEMENTS

Investors are cautioned that certain statements contained in this prospectus as well as in periodic press releases and certain oral statements made by our officials during our presentations are “forward-looking” statements. Forward-looking statements include, without limitation, any statement that may project, indicate or imply future results, events, performance or achievements and may contain the words “expect,” “intend,” “plan,” “anticipate,” “estimate,” “believe,” “will be,” “will continue,” “will likely result” and similar expressions, or future conditional verbs such as “may,” “will,” “should,” “would” and “could.” In addition, any statement concerning future financial performance (including future revenues, earnings or growth rates), ongoing business strategies or prospects and possible actions taken by us, Summit Midstream Partners, LLC or our sponsor, Energy Capital Partners II, LLC, are also forward-looking statements. These forward-looking statements involve various risks and uncertainties, including, but not limited to, those described under the section entitled “Risk Factors” included herein.

Forward-looking statements are based on current expectations and projections about future events and are inherently subject to a variety of risks and uncertainties, many of which are beyond the control of our management team. All forward-looking statements in this prospectus and subsequent written and oral forward-looking statements attributable to us, or to persons acting on our behalf, are expressly qualified in their entirety by the cautionary statements in this paragraph. These risks and uncertainties include, among others:

iv

Developments in any of these areas could cause actual results to differ materially from those anticipated or projected or cause a significant reduction in the market price of our securities.

The foregoing list of risks and uncertainties may not contain all of the risks and uncertainties that could affect us. In addition, in light of these risks and uncertainties, the matters referred to in the forward-looking statements contained or incorporated by reference in this prospectus may not in fact occur. Accordingly, undue reliance should not be placed on these statements. We undertake no obligation to publicly update or revise any forward-looking statements as a result of new information, future events or otherwise, except as otherwise required by law.

v

WHO WE ARE

Unless the context otherwise requires, references in this prospectus to the “Partnership,” “we,” “our,” “us” or like terms, refer to Summit Midstream Partners, LP and its subsidiaries. “Summit Holdings” refers to Summit Midstream Holdings, LLC, a wholly owned subsidiary of the Partnership that may issue any debt securities offered by this prospectus. “Finance Corp.” refers to Summit Midstream Finance Corp., a wholly owned subsidiary of Summit Holdings that may act as co-issuer of any debt securities offered by this prospectus. Our “general partner” refers to Summit Midstream GP, LLC.

General

We are a growth-oriented limited partnership focused on developing, owning and operating midstream energy infrastructure assets that are strategically located in the core producing areas of unconventional resource basins, primarily shale formations, in the continental United States. We were formed in 2012 and our common units are listed on the New York Stock Exchange under the trading symbol “SMLP.”

Our systems gather natural gas from pad sites and central receipt points connected to our systems. Gathered natural gas volumes are compressed, dehydrated, treated and/or processed for delivery to downstream pipelines for ultimate delivery to third-party processing plants and/or end users. We also contract with producers to gather crude oil and produced water from wells connected to our systems for delivery to third-party rail terminals and pipelines in the case of crude oil and to third-party disposal wells in the case of produced water. We generally refer to all of the services our systems provide as gathering services. In addition to our gathering services, we also provide natural gas and crude oil marketing services in and around our gathering systems through our wholly owned subsidiary, Summit Midstream Marketing, LLC.

We are the owner-operator of or have significant ownership interests in the following gathering systems:

1

Summit Holdings was formed under the laws of the State of Delaware on March 30, 2011, is wholly owned by the Partnership and indirectly owns substantially all of the Partnership’s operating assets.

Finance Corp. was incorporated under the laws of the State of Delaware on May 29, 2013, is wholly owned by Summit Holdings, and has no material assets or any liabilities other than as a co-issuer of debt securities. Its activities are limited to co-issuing debt securities and engaging in other activities incidental thereto.

Our principal executive office is located at 1790 Hughes Landing Blvd, Suite 500, The Woodlands, Texas 77380, and our telephone number is (832) 413-4770.

2

RISK FACTORS

Limited partner interests are inherently different from capital stock of a corporation, although many of the business risks to which we are subject are similar to those that would be faced by a corporation engaged in similar businesses. We urge you to carefully consider the risk factors below and included in our most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, each as amended and updated from time to time, which are incorporated by reference into this prospectus and the applicable prospectus supplement, together with all of the other information included in this prospectus, the applicable prospectus supplement and the documents we incorporate by reference, in evaluating an investment in our securities. If any of the risks discussed in the foregoing documents were to materialize, our business, financial condition, results of operations and cash flows could be materially adversely affected and you could lose all or part of your investment. Please read “Forward-Looking Statements.”

The tax treatment of publicly traded partnerships or an investment in our common units could be subject to potential legislative, judicial or administrative changes and differing interpretations, possibly on a retroactive basis.

The present U.S. federal income tax treatment of publicly traded partnerships, including us, or an investment in our common units may be modified by administrative, legislative or judicial changes or differing interpretations at any time. From time to time, members of Congress and the President propose and consider substantive changes to the existing federal income tax laws that affect publicly traded partnerships. If successful, these or other similar proposals could eliminate the qualifying income exception to the treatment of all publicly traded partnerships as corporations, upon which we rely for our treatment as a partnership for U.S. federal income tax purposes. One such proposal could limit our unitholders’ ability to deduct interest expenses for interest in excess of a percentage of our adjusted taxable income.

In addition, the U.S. Treasury Department and the IRS have issued final regulations concerning which activities give rise to qualifying income within the meaning of Section 7704 of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). We do not believe the final regulations adversely affect the amount of our gross income treated as qualifying income or our ability to qualify as a publicly traded partnership. However, any change to these finalized regulations could modify the amount of our gross income that we are able to treat as qualifying income for the purposes of the qualifying income requirement.

Any modification to the U.S. federal income tax laws may be applied retroactively and could make it more difficult or impossible for us to meet the exception for certain publicly traded partnerships to be treated as partnerships for U.S. federal income tax purposes. We are unable to predict whether any of these changes or other proposals will ultimately be enacted. Any such changes could negatively impact the value of an investment in our common units.

If the IRS makes audit adjustments to our income tax returns for tax years beginning after December 31, 2017, it (and some states) may assess and collect any taxes (including any applicable penalties and interest) resulting from such audit adjustment directly from us, in which case we may require our unitholders and former unitholders to reimburse us for such taxes (including any applicable penalties or interest) or, if we are required to bear such payment our cash available for distribution to our unitholders might be substantially reduced.

For tax years beginning before January 1, 2018, any audit adjustments made by the IRS to our income tax returns may result in the payment of additional income taxes by our unitholders and former unitholders in accordance with their interests in us during the year under audit, but generally will not result in a payment of income tax by us. Pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, for tax years beginning after December 31, 2017, if the IRS makes audit adjustments to our income tax returns, it (and some states) may assess and collect any taxes (including any applicable penalties and interest)

3

resulting from such audit adjustment directly from us. Our general partner may elect to cause us to either pay the taxes (including any applicable penalties and interest) directly to the IRS or, if we are eligible, issue a revised Schedule K-1 to each unitholder with respect to an audited and adjusted return. Although our general partner may elect to have our unitholders and former unitholders take such audit adjustment into account and pay any resulting taxes (including applicable penalties or interest) in accordance with their interests in us during the tax year under audit, there can be no assurance that such election will be practical, permissible or effective in all circumstances. If we cannot or do not elect to have our unitholders and former unitholders take such audit adjustments into account through revised Schedules K-1, our current unitholders may bear some or all of the tax liability resulting from such audit adjustment as a result of our direct payment of the tax liability, even if such unitholders did not own common units in us during the tax year under audit. If, as a result of any such audit adjustment, we are required to make direct payments of taxes, penalties and interest, we may require our unitholders and former unitholders to reimburse us for such taxes (including any applicable penalties or interest) or, if we are required to bear such payment our cash available for distribution to our unitholders might be substantially reduced.

4

USE OF PROCEEDS

The actual application of proceeds to us from the sale of any particular offering of securities using this prospectus will be determined at the time of the offering and will be described in the applicable prospectus supplement relating to such offering. The precise amount and timing of the application of these proceeds will depend upon, among other factors, our funding requirements and the availability and cost of other funds.

5

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges for the periods indicated on a consolidated historical basis. For purposes of computing the ratio of earnings to fixed charges, “earnings” are defined as income before taxes and loss from equity method investees plus fixed charges and distributions from equity method investees less capitalized interest. “Fixed charges” consist of interest expensed and capitalized, amortization of debt issuance costs and an estimate of interest within rent expense.

6

DESCRIPTION OF OUR COMMON UNITS

The Common Units

The common units represent limited partner interests in us. The holders of common units are entitled to participate in partnership distributions and are entitled to exercise the rights and privileges available to limited partners under our partnership agreement. For a description of our cash distribution policy, please read this section and “Provisions of Our Partnership Agreement Relating to Cash Distributions.” For a description of the rights and privileges of limited partners under our partnership agreement, including voting rights, please read “The Partnership Agreement.”

Our outstanding common units are listed on the NYSE under the symbol “SMLP,” and any additional common units we issue will also be listed on the NYSE. As of November 3, 2017, there were 73,060,122 common units outstanding. On November 3, 2017, the last reported sales price of our common units on the NYSE was $20.10 per common unit.

Transfer Agent and Registrar

Duties. American Stock Transfer and Trust Company (“AST”) serves as the transfer agent, cash distribution paying agent and registrar for the common units. We will pay all fees charged by the transfer agent for transfers of common units except the following that must be paid by unitholders:

There will be no charge to unitholders for disbursements of our cash distributions. We will indemnify AST, its agents and each of their respective stockholders, directors, officers and employees against all claims and losses that may arise out of acts performed or omitted for its activities in that capacity, except for any liability due to any gross negligence or intentional misconduct of the indemnified person or entity.

Resignation or Removal. The transfer agent may resign, by notice to us, or be removed by us. The resignation or removal of the transfer agent will become effective upon our appointment of a successor transfer agent, cash distribution paying agent and registrar and its acceptance of the appointment. If no successor has been appointed and has accepted the appointment within 30 days after notice of the resignation or removal, our general partner may act as the transfer agent and registrar until a successor is appointed.

Transfer of Common Units

By transfer of common units in accordance with our partnership agreement, each transferee of common units shall be admitted as a limited partner with respect to the common units transferred when such transfer and admission are reflected in our books and records. Each transferee:

Our general partner will cause any transfers to be recorded on our books and records no less frequently than quarterly.

7

We may, at our discretion, treat the nominee holder of a common unit as the absolute owner. In that case, the beneficial holder’s rights are limited solely to those that it has against the nominee holder as a result of any agreement between the beneficial owner and the nominee holder.

Common units are securities and any transfers are subject to the laws governing the transfer of securities.

Until a common unit has been transferred on our books, we and the transfer agent may treat the record holder of the unit as the absolute owner for all purposes, except as otherwise required by law or stock exchange regulations.

8

DESCRIPTION OF OUR PREFERRED UNITS

Issuance of Preferred Units

Our partnership agreement authorizes us to issue an unlimited number of limited partner interests, including preferred units and other equity securities, for any partnership purpose at any time, and from time to time, to such persons for such consideration and on such terms and conditions as our general partner shall determine, all without the approval of the unitholders. In accordance with Delaware law and the provisions of our partnership agreement, any additional partnership interests that we issue may, in the sole discretion of our general partner, have special voting or other rights to which the common units are not entitled.

Should we offer preferred units under this prospectus, a prospectus supplement relating to the particular series of preferred units offered will include the specific terms of those preferred units, including, among other things, the following:

Any preferred units will be fully paid and non-assessable when issued upon full payment of the purchase price therefor. The transfer agent, registrar and paying agent for the preferred units will be designated in the applicable prospectus supplement.

9

DESCRIPTION OF OUR DEBT SECURITIES AND GUARANTEES

The following description, together with the additional information we include in any applicable prospectus supplement, summarizes certain general terms and provisions of the debt securities that we may offer under this prospectus. When we offer to sell a particular series of debt securities, we will describe the specific terms of the series in a supplement to this prospectus. We will also indicate in the supplement to what extent the general terms and provisions described in this prospectus apply to a particular series of debt securities.

As used in this section only, (i) the term “Company” refers only to Summit Midstream Holdings, LLC and not to any of its subsidiaries, (ii) the term “Finance Corp.” refers to Summit Midstream Finance Corp., (iii) the term “Parent” refers to Summit Midstream Partners, LP and not to any of its subsidiaries, and (iv) the terms “we,” “our,” “us” or “Issuers” refer to the Company and Finance Corp., unless expressly stated or the context otherwise requires.

We may issue debt securities either separately, or together with, or upon the conversion or exercise of or in exchange for, other securities described in this prospectus. Debt securities may be our senior, senior subordinated or subordinated obligations and, unless otherwise specified in a supplement to this prospectus, the debt securities will be our direct, unsecured obligations and may be issued in one or more series.

The debt securities will be issued under an indenture between us and U.S. Bank National Association, as trustee. We have summarized select portions of the indenture below. The summary is not complete. The form of the indenture has been filed as an exhibit to the registration statement and you should read the indenture for provisions that may be important to you. In the summary below, we have included references to the section numbers of the indenture so that you can easily locate these provisions. Capitalized terms used in the summary and not defined herein have the meanings specified in the indenture.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of the board of directors of our general partner and set forth or determined in the manner provided in a resolution of the board of directors of our general partner, in an officer’s certificate or by a supplemental indenture. (Section 2.2) The particular terms of each series of debt securities will be described in a prospectus supplement relating to such series (including any pricing supplement or term sheet).

We can issue an unlimited amount of debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium, or at a discount. (Section 2.1) We will set forth in a prospectus supplement (including any pricing supplement or term sheet) relating to any series of debt securities being offered, the aggregate principal amount and the following terms of the debt securities, if applicable:

10

11

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on the federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of the debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of and any premium and interest on any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company (the “Depositary”), or a nominee of the Depositary (we will refer to any debt security represented by a global debt security as a “book-entry debt security”), or a certificate issued in definitive registered form (we will refer to any debt security represented by a certificated security as a “certificated debt security”) as set forth in the applicable prospectus supplement. Except as set forth under the heading “Global Debt Securities and Book-Entry System” below, book-entry debt securities will not be issuable in certificated form.

Certificated Debt Securities. You may transfer or exchange certificated debt securities at any office we maintain in accordance with the terms of the indenture. (Section 2.4) No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange. (Section 2.7)

You may effect the transfer of certificated debt securities and the right to receive the principal of, premium and interest on certificated debt securities only by surrendering the certificate representing those certificated debt securities and either reissuance by us or the trustee of the certificate to the new holder or the issuance by us or the trustee of a new certificate to the new holder.

Global Debt Securities and Book-Entry System. Each global debt security representing book-entry debt securities will be deposited with, or on behalf of, the Depositary, and registered in the name of the Depositary or a nominee of the Depositary.

Covenants

We will set forth in the applicable prospectus supplement any restrictive covenants applicable to any issue of debt securities. (Article IV)

No Protection in the Event of a Change of Control

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions which may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control) which could adversely affect holders of debt securities.

12

Consolidation, Merger and Sale of Assets

The Company may not consolidate with or merge with or into, or convey, transfer or lease all or substantially all of our properties and assets to any person (a “successor person”) unless:

Notwithstanding the above, any of our subsidiaries may consolidate with, merge into or transfer all or part of its properties to us or our Parent, and we may consolidate with, merge into or transfer all or part of our properties to our Parent. (Section 5.1)

Events of Default

“Event of Default” means with respect to any series of debt securities, any of the following:

No Event of Default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an Event of Default with respect to any other series of debt securities. (Section 6.1) The occurrence of certain Events of Default or an acceleration under the indenture may constitute an event of default under certain indebtedness of ours or our subsidiaries outstanding from time to time.

We will provide the trustee written notice of any Default or Event of Default within 30 days of becoming aware of the occurrence of such Default or Event of Default, which notice will describe in reasonable detail the status of such Default or Event of Default and what action we are taking or propose to take in respect thereof. (Section 6.1)

If an Event of Default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than 25% in principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal of (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) and accrued and unpaid interest, if any, on all debt securities of that series. In the case of an Event of Default resulting from certain events of

13

bankruptcy, insolvency or reorganization, the principal (or such specified amount) of and accrued and unpaid interest, if any, on all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, but before a judgment or decree for payment of the money due has been obtained by the trustee, the holders of a majority in principal amount of the outstanding debt securities of that series may rescind and annul the acceleration if all Events of Default, other than the non-payment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the indenture. (Section 6.2) We refer you to the prospectus supplement relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of such discount securities upon the occurrence of an Event of Default.

The indenture provides that the trustee will be under no obligation to exercise any of its rights or powers under the indenture unless the trustee receives indemnity satisfactory to it against any cost, liability or expense which might be incurred by it in exercising such right or power. (Section 7.1(e)) Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series. (Section 6.12)

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

Notwithstanding any other provision in the indenture, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, premium and any interest on that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of payment. (Section 6.8)

The indenture requires us, within 120 days after the end of our fiscal year, to furnish to the trustee a statement as to compliance with the indenture. (Section 4.3) If a Default or Event of Default occurs and is continuing with respect to the securities of any series and if it is known to a responsible officer of the trustee, the trustee shall mail to each securityholder of the debt securities of that series notice of a Default or Event of Default within 90 days after it occurs. The indenture provides that the trustee may withhold notice to the holders of debt securities of any series of any Default or Event of Default (except in payment on any debt securities of that series) with respect to debt securities of that series if the trustee determines in good faith that withholding notice is in the interest of the holders of those debt securities. (Section 7.5)

Modification and Waiver

We and the trustee may modify and amend the indenture or the debt securities of any series without the consent of any holder of any debt security:

14

We may also modify and amend the indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We may not make any modification or amendment without the consent of the holders of each affected debt security then outstanding if that amendment will:

Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive our compliance with provisions of the indenture. (Section 9.2) The holders of a majority in principal amount of the

15

outstanding debt securities of any series may on behalf of the holders of all the debt securities of such series waive any past default under the indenture with respect to that series and its consequences, except a default in the payment of the principal of, premium or any interest on any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration. (Section 6.13)

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, we may be discharged from any and all obligations in respect of the debt securities of any series (subject to certain exceptions). We will be so discharged upon the deposit with the trustee, in trust, of money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. Dollars, government obligations of the government that issued or caused to be issued such currency, that, through the payment of interest and principal in accordance with their terms, will provide money or U.S. government obligations in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants or investment bank to pay and discharge each installment of principal, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities.

This discharge may occur only if, among other things, we have delivered to the trustee an opinion of counsel stating that we have received from, or there has been published by, the United States Internal Revenue Service a ruling or, since the date of execution of the indenture, there has been a change in the applicable United States federal income tax law, in either case to the effect that, and based thereon such opinion shall confirm that, the holders of the debt securities of that series will not recognize income, gain or loss for United States federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to United States federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred. (Section 8.3)

Defeasance of Certain Covenants. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, upon compliance with certain conditions:

The conditions include:

16

Covenant Defeasance and Events of Default. In the event we exercise our option to effect covenant defeasance with respect to any series of debt securities and the debt securities of that series are declared due and payable because of the occurrence of any Event of Default, the amount of money and/or U.S. government obligations or foreign government obligations on deposit with the trustee will be sufficient to pay amounts due on the debt securities of that series at the time of their stated maturity but may not be sufficient to pay amounts due on the debt securities of that series at the time of the acceleration resulting from the Event of Default. However, we shall remain liable for those payments. (Section 8.4)

No Personal Liability of Directors, Officers, Employees or Unitholders

None of our past, present or future directors, officers, employees or unitholders, as such, will have any liability for any of our obligations under the debt securities or the indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a debt security, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the debt securities. However, this waiver and release may not be effective to waive liabilities under U.S. federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Governing Law

The indenture and the debt securities, including any claim or controversy arising out of or relating to the indenture or the debt securities, will be governed by the laws of the State of New York (without regard to the conflicts of laws provisions thereof other than Section 5-1401 of the General Obligations Law). (Section 10.10)

17

PROVISIONS OF OUR PARTNERSHIP AGREEMENT RELATING TO CASH DISTRIBUTIONS

Set forth below is a summary of the significant provisions of our partnership agreement that relate to cash distributions.

Distributions of Available Cash

General. Our partnership agreement requires that, within 45 days after the end of each quarter, we distribute all of our available cash to unitholders of record on the applicable record date.

Definition of Available Cash. Available cash generally means, for any quarter, all cash on hand at the end of that quarter:

The purpose and effect of the last bullet point above is to allow our general partner, if it so decides, to use cash from working capital borrowings made after the end of the quarter but on or before the date of determination of available cash for that quarter to pay distributions to unitholders. Under our partnership agreement, working capital borrowings are generally borrowings that are made under a credit facility, commercial paper facility or similar financing arrangement, and in all cases are used solely for working capital purposes or to pay distributions to partners, and with the intent of the borrower to repay such borrowings within 12 months with funds other than from additional working capital borrowings. The proceeds of working capital borrowings increase operating surplus and repayments of working capital borrowings are generally operating expenditures (as described below) and thus reduce operating surplus when repayments are made. However, if working capital borrowings, which increase operating surplus, are not repaid during the 12-month period following the borrowing, they will be deemed repaid at the end of such period, thus decreasing operating surplus at such time. When such working capital borrowings are in fact repaid, they will not be treated as a further reduction in operating surplus because operating surplus will have been previously reduced by the deemed repayment.

Intent to Distribute At Least the Minimum Quarterly Distribution. We intend to make a quarterly cash distribution to the holders of our common units to the extent we have sufficient cash from our operations after the establishment of cash reserves and payment of costs and expenses, including reimbursements of expenses to our general partner. Our quarterly distribution declared for the quarter ended September 30, 2017 is $0.575 per common unit, or $2.30 annualized. However, there is no guarantee that we will continue to pay a quarterly distribution on our common units at that level or at all. Even if our cash distribution policy is not modified or revoked, the amount of distributions paid under our policy and the decision to make any distribution is determined by our general partner, taking into consideration the terms of our partnership agreement.

General Partner Interest and Incentive Distribution Rights. Our general partner is currently entitled to a maximum 2.0% of all distributions that we make prior to our liquidation. Our general partner has the right, but

18

not the obligation, to contribute a proportionate amount of capital to us to maintain its current general partner interest. Our general partner’s 2.0% interest in our distributions will be reduced if we issue additional units in the future and our general partner does not contribute a proportionate amount of capital to us to maintain its 2.0% general partner interest.

Our general partner also currently holds incentive distribution rights that entitle it to receive increasing percentages, up to a maximum of 50.0%, of the cash we distribute from operating surplus (as defined below) in excess of $0.46 per unit per quarter. The maximum distribution of 50.0% includes distributions paid to our general partner on its 2.0% general partner interest and assumes that our general partner maintains its general partner interest at 2.0%. The maximum distribution of 50.0% does not include any distributions that our general partner may receive on any common units that it owns.

Operating Surplus and Capital Surplus

General. All cash distributed to unitholders will be characterized as either being paid from “operating surplus” or “capital surplus.” We treat distributions of available cash from operating surplus differently than distributions of available cash from capital surplus.

Operating Surplus. We define operating surplus as:

As described above, operating surplus does not reflect actual cash on hand that is available for distribution to our unitholders and is not limited to cash generated by operations. For example, it includes a provision that will enable us, if we choose, to distribute as operating surplus up to $50.0 million of cash we receive in the future

19

from non-operating sources such as asset sales, issuances of securities and long-term borrowings that would otherwise be distributed as capital surplus. In addition, the effect of including, as described above, certain cash distributions on equity interests in operating surplus is to increase operating surplus by the amount of any such cash distributions. As a result, we may also distribute as operating surplus up to the amount of any such cash that we receive from non-operating sources.

We define interim capital transactions as (i) borrowings, refinancings or refundings of indebtedness (other than working capital borrowings and items purchased on open account in the ordinary course of business) and sales of debt securities, (ii) sales of equity securities, (iii) sales or other dispositions of assets, other than sales or other dispositions of inventory, accounts receivable and other assets in the ordinary course of business and sales or other dispositions of assets as part of ordinary course asset retirements or replacements and (iv) capital contributions received.

We define operating expenditures as all of our cash expenditures, including, but not limited to, taxes, compensation of employees, officers and directors of our general partner, reimbursements of expenses to our general partner and its affiliates, interest payments, payments made in the ordinary course of business under interest rate hedge contracts and commodity hedge contracts (provided that (i) with respect to amounts paid in connection with the initial purchase of an interest rate hedge contract or a commodity hedge contract, such amounts will be amortized over the life of the applicable interest rate hedge contract or commodity hedge contract and (ii) payments made in connection with the termination of any interest rate hedge contract or commodity hedge contract prior to the expiration of its stipulated settlement or termination date will be included in operating expenditures in equal quarterly installments over the remaining scheduled life of such interest rate hedge contract or commodity hedge contract), and repayment of working capital borrowings; provided, however, that operating expenditures do not include:

Capital Surplus. Capital surplus is defined in our partnership agreement as any distribution of available cash in excess of our cumulative operating surplus. Accordingly, except as described above, capital surplus would generally be generated by:

Characterization of Cash Distributions. Our partnership agreement requires that we treat all available cash distributed as coming from operating surplus until the sum of all available cash distributed since the closing of our initial public offering equals the operating surplus from the closing of our initial public offering through the

20

end of the quarter immediately preceding that distribution. Our partnership agreement requires that we treat any amount distributed in excess of operating surplus, regardless of its source, as capital surplus. We do not anticipate that we will make any distributions from capital surplus.

Capital Expenditures

Maintenance capital expenditures are cash expenditures (including expenditures for the addition or improvement to, or the replacement of, our capital assets or for the acquisition of existing, or the construction or development of new, capital assets) made to maintain our operating income or operating capacity over the long term. A primary component of maintenance capital expenditures are expenditures to connect additional wells to our gathering systems to offset natural declines in production over time and for routine equipment and pipeline maintenance or replacement due to obsolescence.

Expansion capital expenditures are cash expenditures incurred for acquisitions or capital improvements that we expect will increase our operating income or operating capacity over the long term. Expansion capital expenditures include interest payments (and related fees) on debt incurred and issued to finance the construction of such capital improvement and paid in respect of the period beginning on the date that we enter into a binding obligation to commence construction of the capital improvement and ending on the earlier to occur of the date that such capital improvement commences commercial service and the date that such capital improvement is abandoned or disposed of. Examples of expansion capital expenditures include the acquisition of equipment, or the construction, development or acquisition of additional pipeline or treating capacity or new compression capacity, to the extent such capital expenditures are expected to expand our long-term operating capacity or operating income.

Capital expenditures that are made in part for maintenance capital purposes and in part for expansion capital purposes will be allocated between maintenance capital expenditures and expansion capital expenditures by our general partner.

Distributions of Available Cash from Operating Surplus

We make distributions of available cash from operating surplus for any quarter in the following manner:

The preceding discussion is based on the assumptions that our general partner maintains its 2.0% general partner interest and that we do not issue additional classes of equity securities.

General Partner Interest and Incentive Distribution Rights

Our general partner is currently entitled to 2.0% of all distributions that we make prior to our liquidation. Our general partner has the right, but not the obligation, to contribute a proportionate amount of capital to us in order to maintain its 2.0% general partner interest if we issue additional units. Our general partner’s 2.0% interest, and the percentage of our cash distributions to which it is entitled from such 2.0% interest, will be proportionately reduced if we issue additional units in the future (other than the issuance of common units upon a reset of the incentive distribution rights) and our general partner does not contribute a proportionate amount of capital to us in order to maintain its 2.0% general partner interest. Our partnership agreement does not require that our general partner fund its capital contribution with cash. It may instead fund its capital contribution by the contribution to us of common units or other property.

21

Incentive distribution rights represent the right to receive an increasing percentage (13.0%, 23.0% and 48.0%) of quarterly distributions of available cash from operating surplus after the minimum quarterly distribution and the target distribution levels have been achieved. Our general partner currently holds the incentive distribution rights, but may transfer these rights separately from its general partner interest at any time without the approval of any person.

The following discussion assumes that our general partner maintains its 2.0% general partner interest and that our general partner continues to own the incentive distribution rights.

If for any quarter we have distributed available cash from operating surplus to the common unitholders in an amount equal to the minimum quarterly distribution, we will distribute any additional available cash from operating surplus for that quarter among the unitholders and the general partner in the following manner:

Percentage Allocations of Available Cash from Operating Surplus

The following table illustrates the percentage allocations of available cash from operating surplus between the unitholders and our general partner based on the specified target distribution levels. The amounts set forth under “Marginal Percentage Interest in Distributions” are the percentage interests of our general partner and the unitholders in any available cash from operating surplus we distribute up to and including the corresponding amount in the column “Total Quarterly Distribution Per Unit Target Amount.” The percentage interests shown for our unitholders and our general partner for the minimum quarterly distribution are also applicable to quarterly distribution amounts that are less than the minimum quarterly distribution. The percentage interests set forth below for our general partner include its 2.0% general partner interest and assume that our general partner has contributed any additional capital necessary to maintain its 2.0% general partner interest and our general partner has not transferred its incentive distribution rights.

General Partner’s Right to Reset Incentive Distribution Levels

Our general partner, as the initial holder of our incentive distribution rights, has the right under our partnership agreement to elect to relinquish the right to receive incentive distribution payments based on the initial target distribution levels and to reset, at higher levels, the minimum quarterly distribution amount and target distribution levels upon which the incentive distribution payments to our general partner would be set. If our general partner transfers all or a portion of our incentive distribution rights in the future, then the holder or holders of a majority of our incentive distribution rights will be entitled to exercise this right. The following

22

discussion assumes that our general partner holds all of the incentive distribution rights at the time that a reset election is made. Our general partner’s right to reset the minimum quarterly distribution amount and the target distribution levels upon which the incentive distributions payable to our general partner are based may be exercised, without approval of our unitholders or the conflicts committee of our general partner, at any time when we have made cash distributions to the holders of the incentive distribution rights at the highest level of incentive distribution for each of the four consecutive fiscal quarters immediately preceding such time and the amount of each such distribution did not exceed adjusted operating surplus for such quarter, respectively. If our general partner and its affiliates are not the holders of a majority of the incentive distribution rights at the time an election is made to reset the minimum quarterly distribution amount and the target distribution levels, then the proposed reset will be subject to the prior written concurrence of the general partner that the conditions described above have been satisfied. The reset minimum quarterly distribution amount and target distribution levels will be higher than the minimum quarterly distribution amount and the target distribution levels prior to the reset such that our general partner will not receive any incentive distributions under the reset target distribution levels until cash distributions per unit following this event increase as described below. We anticipate that our general partner would exercise this reset right in order to facilitate acquisitions or internal growth projects that would otherwise not be sufficiently accretive to cash distributions per common unit, taking into account the existing levels of incentive distribution payments being made to our general partner.

In connection with the resetting of the minimum quarterly distribution amount and the target distribution levels and the corresponding relinquishment by our general partner of incentive distribution payments based on the target distributions prior to the reset, our general partner will be entitled to receive a number of newly issued common units and general partner units based on a predetermined formula described below that takes into account the “cash parity” value of the average cash distributions related to the incentive distribution rights received by our general partner for the two quarters immediately preceding the reset event as compared to the average cash distributions per common unit during that two-quarter period. Our general partner will be issued the number of general partner units necessary to maintain our general partner’s interest in us immediately prior to the reset election.

The number of common units that our general partner would be entitled to receive from us in connection with a resetting of the minimum quarterly distribution amount and the target distribution levels then in effect would be equal to the quotient determined by dividing (x) the average aggregate amount of cash distributions received by our general partner in respect of its incentive distribution rights during the two consecutive fiscal quarters ended immediately prior to the date of such reset election by (y) the average of the aggregate amount of cash distributed per common unit during each of these two quarters.

Following a reset election, the minimum quarterly distribution amount will be reset to an amount equal to the average cash distribution amount per unit for the two fiscal quarters immediately preceding the reset election (which amount we refer to as the “reset minimum quarterly distribution”) and the target distribution levels will be reset to be correspondingly higher such that we would distribute all of our available cash from operating surplus for each quarter thereafter as follows:

23

Distributions From Capital Surplus

How Distributions from Capital Surplus Will Be Made. We will make distributions of available cash from capital surplus, if any, in the following manner:

The preceding discussion is based on the assumption that our general partner maintains its 2.0% general partner interest and that we do not issue additional classes of equity securities.

Effect of a Distribution from Capital Surplus. Our partnership agreement treats a distribution of capital surplus as the repayment of the initial unit price from our initial public offering, which is a return of capital. The initial public offering price less any distributions of capital surplus per unit is referred to as the “unrecovered initial unit price.” Each time a distribution of capital surplus is made, the minimum quarterly distribution and the target distribution levels will be reduced in the same proportion as the corresponding reduction in the unrecovered initial unit price. Because distributions of capital surplus will reduce the minimum quarterly distribution and target distribution levels after any of these distributions are made, it may be easier for our general partner to receive incentive distributions. However, any distribution of capital surplus before the unrecovered initial unit price is reduced to zero cannot be applied to the payment of the minimum quarterly distribution.

Once we distribute capital surplus on a unit issued in our initial public offering in an amount equal to the initial unit price, we will reduce the minimum quarterly distribution and the target distribution levels to zero. We will then make all future distributions from operating surplus, with 50.0% being paid to the unitholders, pro rata, and 50.0% to our general partner. The percentage interests shown for our general partner include its 2.0% general partner interest and assume that our general partner has not transferred the incentive distribution rights.

Adjustment to the Minimum Quarterly Distribution and Target Distribution Levels

In addition to adjusting the minimum quarterly distribution and target distribution levels to reflect a distribution of capital surplus, if we combine our units into fewer units or subdivide our units into a greater number of units, we will proportionately adjust:

For example, if a two-for-one split of the common units should occur, the minimum quarterly distribution, the target distribution levels and the unrecovered initial unit price would each be reduced to 50% of its initial level. We will not make any adjustment by reason of the issuance of additional units for cash or property.

In addition, if legislation is enacted or if existing law is modified or interpreted by a governmental authority, so that we become taxable as a corporation or otherwise subject to taxation as an entity for federal, state or local income tax purposes, our partnership agreement specifies that the minimum quarterly distribution and the target distribution levels for each quarter may be reduced by multiplying each distribution level by a fraction, the numerator of which is available cash for that quarter (reduced by the amount of the estimated tax liability for such quarter payable by reason of such legislation or interpretation) and the denominator of which is the sum of available cash for that quarter (reduced by the amount of the estimated tax liability for such quarter payable by

24

reason of such legislation or interpretation) plus our general partner’s estimate of our aggregate liability for the quarter for such income taxes payable by reason of such legislation or interpretation. To the extent that the actual tax liability differs from the estimated tax liability for any quarter, the difference will be accounted for in subsequent quarters.

Distributions of Cash Upon Liquidation

General. If we dissolve in accordance with our partnership agreement, we will sell or otherwise dispose of our assets in a process called liquidation. We will first apply the proceeds of liquidation to the payment of our creditors. We will distribute any remaining proceeds to the unitholders and our general partner, in accordance with their capital account balances, as adjusted to reflect any gain or loss upon the sale or other disposition of our assets in liquidation.

Manner of Adjustments for Gain. The manner of the adjustment for gain is set forth in our partnership agreement. Upon liquidation, we will allocate any gain to our partners in the following manner:

The percentages set forth above are based on the assumption that our general partner has not transferred its incentive distribution rights and that we do not issue additional classes of equity securities.

Manner of Adjustments for Losses. Upon liquidation, we will generally allocate any loss to our general partner and the unitholders in the following manner:

25

Adjustments to Capital Accounts. Our partnership agreement requires that we make adjustments to capital accounts upon the issuance of additional units. In this regard, our partnership agreement specifies that we allocate any unrealized and, for tax purposes, unrecognized gain resulting from the adjustments to the unitholders and the general partner in the same manner as we allocate gain upon liquidation. In the event that we make positive adjustments to the capital accounts upon the issuance of additional units, our partnership agreement requires that we generally allocate any later negative adjustments to the capital accounts resulting from the issuance of additional units or upon our liquidation in a manner which results, to the extent possible, in the partners’ capital account balances equaling the amount which they would have been if no earlier positive adjustments to the capital accounts had been made. In contrast to the allocations of gain, and except as provided above, we generally will allocate any unrealized and unrecognized loss resulting from the adjustments to capital accounts upon the issuance of additional units to the unitholders and our general partner based on their respective percentage ownership of us. If we make negative adjustments to the capital accounts as a result of such loss, future positive adjustments resulting from the issuance of additional units will be allocated in a manner designed to reverse the prior negative adjustments, and special allocations will be made upon liquidation in a manner that results, to the extent possible, in our unitholders’ capital account balances equaling the amounts they would have been if no earlier adjustments for loss had been made.

26

THE PARTNERSHIP AGREEMENT

The following is a summary of the material provisions of our partnership agreement. We will provide prospective investors with a copy of our partnership agreement upon request at no charge.

We summarize the following provisions of our partnership agreement elsewhere in this prospectus:

Organization and Duration

We were organized in Delaware in May 2012 and have a perpetual existence.

Purpose

Our purpose under our partnership agreement is limited to any business activities that are approved by our general partner and in any event that lawfully may be conducted by a limited partnership organized under Delaware law; provided that our general partner may not cause us to engage, directly or indirectly, in any business activity that our general partner determines would be reasonably likely to cause us to be treated as an association taxable as a corporation or otherwise taxable as an entity for federal income tax purposes.

Although our general partner has the power to cause us, our operating company and its subsidiaries to engage in activities other than the business of gathering, treating, processing and transporting natural gas and providing crude oil and produced water gathering services, our general partner has no current plans to do so and may decline to do so free of any duty or obligation whatsoever to us or our unitholders, other than the implied contractual covenant of good faith and fair dealing. Our general partner is generally authorized to perform all acts it determines to be necessary or appropriate to carry out our purposes and to conduct our business.

Cash Distributions

Our partnership agreement specifies the manner in which we will make cash distributions to holders of our common units and other partnership interests as well as to our general partner in respect of its general partner interest and its incentive distribution rights. For a description of these cash distribution provisions, please read “Provisions of Our Partnership Agreement Relating to Cash Distributions.”

Capital Contributions

Unitholders are not obligated to make additional capital contributions, except as described below under “—Limited Liability.”

For a discussion of our general partner’s right to contribute capital to maintain its 2.0% general partner interest if we issue additional units, please read “—Issuance of Additional Partnership Interests.”

Voting Rights

The following is a summary of the unitholder vote required for approval of the matters specified below. Matters that require the approval of a “unit majority” require the approval of a majority of the common units.

27

In voting their common units, our general partner and its affiliates will have no fiduciary duty or obligation whatsoever to us or our unitholders, including any duty to act in the best interests of us or our unitholders, other than the implied contractual covenant of good faith and fair dealing.

28

Limited Liability

Assuming that a limited partner does not participate in the control of our business within the meaning of the Delaware Revised Uniform Limited Partnership Act (the “Delaware Act”) and that it otherwise acts in conformity with the provisions of our partnership agreement, its liability under the Delaware Act will be limited, subject to possible exceptions, to the amount of capital it is obligated to contribute to us for its common units plus its share of any undistributed profits and assets. If it were determined, however, that the right of, or exercise of the right by, the limited partners as a group:

constituted “participation in the control” of our business for the purposes of the Delaware Act, then the limited partners could be held personally liable for our obligations under the laws of Delaware, to the same extent as our general partner. This liability would extend to persons who transact business with us who reasonably believe that a limited partner is a general partner. Neither our partnership agreement nor the Delaware Act specifically provides for legal recourse against our general partner if a limited partner were to lose limited liability through any fault of our general partner. While this does not mean that a limited partner could not seek legal recourse, we know of no precedent for such a claim in Delaware case law.

Under the Delaware Act, a limited partnership may not make a distribution to a partner if, after the distribution, all liabilities of the limited partnership, other than liabilities to partners on account of their partnership interests and liabilities for which the recourse of creditors is limited to specific property of the partnership, would exceed the fair value of the assets of the limited partnership, except that the fair value of property that is subject to a liability for which the recourse of creditors is limited is included in the assets of the limited partnership only to the extent that the fair value of that property exceeds that liability. For the purpose of determining the fair value of the assets of a limited partnership, the Delaware Act provides that the fair value of property subject to liability for which recourse of creditors is limited shall be included in the assets of the limited partnership only to the extent that the fair value of that property exceeds the nonrecourse liability. The Delaware Act provides that a limited partner who receives a distribution and knew at the time of the distribution that the distribution was in violation of the Delaware Act shall be liable to the limited partnership for the amount of the distribution for three years. Under the Delaware Act, a substituted limited partner of a limited partnership is liable for the obligations of its assignor to make contributions to the partnership, except that such person is not obligated for liabilities unknown to it at the time it became a limited partner and that could not be ascertained from the partnership agreement.

Our subsidiaries conduct business in eight states and we may have subsidiaries that conduct business in other states in the future. Maintenance of our limited liability as a member of our primary operating subsidiary, Summit Holdings, which we refer to as our “operating company,” may require compliance with legal requirements in the jurisdictions in which the operating company conducts business, including qualifying our subsidiaries to do business there.

Limitations on the liability of members or limited partners for the obligations of a limited liability company or limited partnership have not been clearly established in many jurisdictions. If, by virtue of our ownership interest in our operating company or otherwise, it were determined that we were conducting business in any state without compliance with the applicable limited partnership or limited liability company statute, or that the right or exercise of the right by the limited partners as a group to remove or replace our general partner, to approve some amendments to our partnership agreement, or to take other action under our partnership agreement constituted “participation in the control” of our business for purposes of the statutes of any relevant jurisdiction, then the limited partners could be held personally liable for our obligations under the law of that jurisdiction to the same extent as our general partner under the circumstances. We will operate in a manner that our general partner considers reasonable and necessary or appropriate to preserve the limited liability of the limited partners.

29

Issuance of Additional Partnership Interests

Our partnership agreement authorizes us to issue an unlimited number of additional partnership interests for the consideration and on the terms and conditions determined by our general partner without the approval of our limited partners.

It is possible that we will fund acquisitions through the issuance of additional common units, preferred units or other partnership interests. Holders of any additional common units we issue will be entitled to share equally with the then-existing holders of common units in our distributions of available cash. In addition, the issuance of additional common units, preferred units or other partnership interests may dilute the value of the interests of the then-existing holders of common units in our net assets.

In accordance with Delaware law and the provisions of our partnership agreement, we may also issue additional partnership interests (such as preferred units) that, as determined by our general partner, may have rights to distributions or special voting rights to which the common units are not entitled. In addition, our partnership agreement does not prohibit our subsidiaries from issuing equity securities, which may effectively rank senior to the common units.

Upon issuance of additional partnership interests (other than the issuance of common units upon a reset of the incentive distribution rights) our general partner will be entitled, but not required, to make additional capital contributions to the extent necessary to maintain its 2.0% general partner interest in us. Our general partner’s 2.0% interest in us will be reduced if we issue additional units in the future (other than in those circumstances described above) and our general partner does not contribute a proportionate amount of capital to us to maintain its 2.0% general partner interest. Moreover, our general partner has the right, which it may from time to time assign in whole or in part to any of its affiliates, to purchase common units or other partnership interests whenever, and on the same terms that, we issue those interests to persons other than our general partner and its affiliates, to the extent necessary to maintain the percentage interest of the general partner and its affiliates, including such interest represented by common units, that existed immediately prior to each issuance. The holders of common units do not have preemptive rights under our partnership agreement to acquire additional common units or other partnership interests.

Amendment of Our Partnership Agreement

General. Amendments to our partnership agreement may be proposed only by our general partner. However, our general partner has no duty or obligation to propose any amendment and may decline to do so free of any duty or obligation whatsoever to us or our unitholders, including any duty to act in the best interests of our partnership or our unitholders, other than the implied contractual covenants of good faith and fair dealing. In order to adopt a proposed amendment, other than the amendments discussed below, our general partner must seek written approval of the holders of the number of units required to approve the amendment or call a meeting of the limited partners to consider and vote upon the proposed amendment. Except as described below, an amendment must be approved by a unit majority.

Prohibited Amendments. No amendment may be made that would:

The provision of our partnership agreement preventing the amendments having the effects described in the clauses above can be amended upon the approval of the holders of at least 90.0% of the outstanding units, voting

30

as a single class (including units owned by our general partner and its affiliates). As of November 3, 2017, our general partner and its affiliates beneficially owned approximately 43.5% of the outstanding common units.

No Unitholder Approval. Our general partner may generally make amendments to our partnership agreement without the approval of any limited partner to reflect:

In addition, our general partner may make amendments to our partnership agreement, without the approval of any limited partner, if our general partner determines that those amendments:

31

Opinion of Counsel and Limited Partner Approval. Our general partner will not be required to obtain an opinion of counsel that an amendment will not result in a loss of limited liability to the limited partners or result in our being treated as an entity for federal income tax purposes in connection with any of the amendments described above under “—No Unitholder Approval.” No other amendments to our partnership agreement will become effective without the approval of holders of at least 90.0% of the outstanding units voting as a single class unless we first obtain an opinion of counsel to the effect that the amendment will not affect the limited liability under applicable law of any of our limited partners.

In addition to the above restrictions, any amendment that would have a material adverse effect on the rights or preferences of any type or class of outstanding units in relation to other classes of units will require the approval of at least a majority of the type or class of units so affected. Any amendment that reduces the voting percentage required to take any action must be approved by the affirmative vote of limited partners whose aggregate outstanding units constitute not less than the percentage sought to be reduced. Any amendment that would increase the percentage of units required to remove our general partner must be approved by the affirmative vote of limited partners whose aggregate outstanding units constitute not less than 90.0% of outstanding units. Any amendment that would increase the percentage of units required to call a meeting of unitholders must be approved by the affirmative vote of unitholders whose aggregate outstanding units constitute at least a majority of the outstanding units.

Merger, Sale or Other Disposition of Assets

A merger or consolidation of us requires the prior consent of our general partner. However, our general partner has no duty or obligation to consent to any merger or consolidation and may decline to do so free of any duty or obligation whatsoever to us or the limited partners, including any duty to act in the best interests of our partnership or our unitholders, other than the implied contractual covenant of good faith and fair dealing.

In addition, our partnership agreement generally prohibits our general partner, without the prior approval of the holders of a unit majority, from causing us to, among other things, sell, exchange or otherwise dispose of all or substantially all of our and our subsidiaries’ assets in a single transaction or a series of related transactions, including by way of merger, consolidation, other combination or sale of ownership interests of our subsidiaries. Our general partner may, however, mortgage, pledge, hypothecate or grant a security interest in all or substantially all of our and our subsidiaries’ assets without that approval. Our general partner may also sell all or substantially all of our and our subsidiaries’ assets under a foreclosure or other realization upon those encumbrances without that approval. Finally, our general partner may consummate any merger without the prior approval of our unitholders if we are the surviving entity in the transaction, our general partner has received an opinion of counsel regarding limited liability and tax matters, the transaction would not result in a material amendment to the partnership agreement (other than an amendment that the general partner could adopt without the consent of the limited partners), each of our units will be an identical unit of our partnership following the transaction and the partnership interests to be issued do not exceed 20.0% of our outstanding partnership interests immediately prior to the transaction.

If the conditions specified in our partnership agreement are satisfied, our general partner may convert us or any of our subsidiaries into a new limited liability entity or merge us or any of our subsidiaries into, or convey all of our assets to, a newly formed limited liability entity, if the sole purpose of that conversion, merger or conveyance is to effect a mere change in our legal form into another limited liability entity, our general partner has received an opinion of counsel regarding limited liability and tax matters and the governing instruments of the new entity

32

provide the limited partners and our general partner with the same rights and obligations as contained in our partnership agreement. Our unitholders are not entitled to dissenters’ rights of appraisal under our partnership agreement or applicable Delaware law in the event of a conversion, merger or consolidation, a sale of substantially all of our assets or any other similar transaction or event.

Termination and Dissolution

We will continue as a limited partnership until dissolved under our partnership agreement. We will dissolve upon:

Upon a dissolution under the first clause above, the holders of a unit majority may also elect, within specific time limitations, to continue our business on the same terms and conditions described in our partnership agreement and appoint as a successor general partner an entity approved by the holders of units representing a unit majority, subject to our receipt of an opinion of counsel to the effect that:

Liquidation and Distribution of Proceeds

Upon our dissolution, unless we are continued as a limited partnership, the liquidator authorized to wind up our affairs will, acting with all of the powers of our general partner that are necessary or appropriate, liquidate our assets and apply the proceeds of the liquidation as described in “Provisions of Our Partnership Agreement Relating to Cash Distributions—Distributions of Cash Upon Liquidation.” The liquidator may defer liquidation or distribution of our assets for a reasonable period of time if it determines that an immediate sale or distribution would be impractical or would cause undue loss to our partners. The liquidator may distribute our assets, in whole or in part, in kind if it determines that a sale would be impractical or would cause undue loss to the partners.

Withdrawal or Removal of Our General Partner

Except as described below, our general partner has agreed not to withdraw voluntarily as our general partner prior to December 31, 2022 without obtaining the approval of the holders of at least a majority of the outstanding common units, excluding common units held by the general partner and its affiliates, and furnishing an opinion of counsel regarding limited liability and tax matters. On or after December 31, 2022, our general partner may withdraw as general partner without first obtaining approval of any unitholder by giving at least 90 days’ written notice, and that withdrawal will not constitute a violation of our partnership agreement. Notwithstanding the information above, our general partner may withdraw without unitholder approval upon 90 days’ notice to the limited partners if at least 50.0% of the outstanding common units are held or controlled by one person and its

33

affiliates, other than our general partner and its affiliates. In addition, our partnership agreement permits our general partner in some instances to sell or otherwise transfer all of its general partner interest in us without the approval of the unitholders. Please read “—Transfer of General Partner Interest” and “—Transfer of Incentive Distribution Rights.”

Upon withdrawal of our general partner under any circumstances, other than as a result of a transfer by our general partner of all or a part of its general partner interest in us, the holders of a unit majority may select a successor to that withdrawing general partner. If a successor is not elected, or is elected but an opinion of counsel regarding limited liability and tax matters cannot be obtained, we will be dissolved, wound up and liquidated, unless within a specified period of time after that withdrawal, the holders of a unit majority agree in writing to continue our business and to appoint a successor general partner. Please read “—Termination and Dissolution.”

Our general partner may not be removed unless that removal is approved by the vote of the holders of not less than 66 ²⁄₃% of all outstanding units, voting together as a single class, including units held by our general partner and its affiliates, and we receive an opinion of counsel regarding limited liability and tax matters. Any removal of our general partner is also subject to the approval of a successor general partner by the vote of the holders of a majority of the outstanding common units. The ownership of more than 33 ¹⁄₃% of the outstanding units by our general partner and its affiliates gives them the ability to prevent our general partner’s removal.

Our partnership agreement also provides that if our general partner is removed as our general partner under circumstances where cause does not exist and units held by the general partner and its affiliates are not voted in favor of that removal, our general partner will have the right to convert its general partner interest and its incentive distribution rights into common units or receive cash in exchange for those interests based on the fair market value of those interests as of the effective date of its removal.

In the event of removal of our general partner under circumstances where cause exists or withdrawal of our general partner where that withdrawal violates our partnership agreement, a successor general partner will have the option to purchase the general partner interest and incentive distribution rights of the departing general partner for a cash payment equal to the fair market value of those interests. Under all other circumstances where our general partner withdraws or is removed by the limited partners, the departing general partner will have the option to require the successor general partner to purchase the general partner interest of the departing general partner and its incentive distribution rights for their fair market value. In each case, this fair market value will be determined by agreement between the departing general partner and the successor general partner. If no agreement is reached, an independent investment banking firm or other independent expert selected by the departing general partner and the successor general partner will determine the fair market value. Or, if the departing general partner and the successor general partner cannot agree upon an expert, then an expert chosen by agreement of the experts selected by each of them will determine the fair market value.

If the option described above is not exercised by either the departing general partner or the successor general partner, the departing general partner’s general partner interest and its incentive distribution rights will automatically convert into common units equal to the fair market value of those interests as determined by an investment banking firm or other independent expert selected in the manner described in the preceding paragraph.

In addition, we will be required to reimburse the departing general partner for all amounts due to it, including, without limitation, all employee-related liabilities, including severance liabilities, incurred in connection with the termination of any employees employed by the departing general partner or its affiliates for our benefit.

Transfer of General Partner Interest

Except for transfer by our general partner of all, but not less than all, of its general partner interest to:

34

our general partner may not transfer all or any of its general partner interest to another person prior to December 31, 2022 without the approval of the holders of at least a majority of the outstanding common units, excluding common units held by our general partner and its affiliates. As a condition of this transfer, the transferee must, among other things, assume the rights and duties of our general partner, agree to be bound by the provisions of our partnership agreement and furnish an opinion of counsel regarding limited liability and tax matters.

Our general partner and its affiliates may, at any time, transfer units to one or more persons, without unitholder approval.

Transfer of Ownership Interests in Our General Partner

At any time, the owners of our general partner may sell or transfer all or part of their ownership interests in our general partner to an affiliate or a third party without the approval of our unitholders.

Transfer of Incentive Distribution Rights

Our general partner may transfer any or all of its incentive distribution rights to an affiliate or a third party without unitholder approval.

Change of Management Provisions

Our partnership agreement contains specific provisions that are intended to discourage a person or group from attempting to remove our general partner or otherwise change our management. Please read “—Withdrawal or Removal of Our General Partner” for a discussion of certain consequences of the removal of our general partner. If any person or group, other than our general partner and its affiliates, acquires beneficial ownership of 20.0% or more of any class of units, that person or group loses voting rights on all of its units. This loss of voting rights does not apply to any person or group that acquires the units directly from our general partner or its affiliates or any transferee of that person or group that is approved by our general partner or to any person or group who acquires the units with the prior approval of the board of directors of our general partner. Please read “—Meetings; Voting.”

Limited Call Right

If at any time our general partner and its affiliates own more than 80.0% of the then-issued and outstanding limited partner interests of any class, our general partner will have the right, which it may assign in whole or in part to any of its affiliates or to us, to acquire all, but not less than all, of the remaining limited partner interests of the class held by unaffiliated persons as of a record date to be selected by our general partner, on at least 10, but not more than 60, days’ notice. The purchase price in the event of this purchase is the greater of:

As a result of our general partner’s right to purchase outstanding limited partner interests, a holder of limited partner interests may have his limited partner interests purchased at an undesirable time or price. The tax consequences to a unitholder of the exercise of this call right are the same as a sale by that unitholder of his common units in the market. Please read “Material U.S. Federal Income Tax Consequences—Disposition of Units.”

35

Meetings; Voting

Except as described below regarding a person or group owning 20.0% or more of any class of units then outstanding, unitholders who are record holders of units on the record date will be entitled to notice of, and to vote at, meetings of our limited partners and to act upon matters for which approvals may be solicited.

Our general partner does not anticipate that any meeting of unitholders will be called in the foreseeable future. Any action that is required or permitted to be taken by the unitholders may be taken either at a meeting of the unitholders or without a meeting if consents in writing describing the action so taken are signed by holders of the number of units necessary to authorize or take that action at a meeting. Meetings of the unitholders may be called by our general partner or by unitholders owning at least 20.0% of the outstanding units of the class for which a meeting is proposed. Unitholders may vote either in person or by proxy at meetings. The holders of a majority of the outstanding units of the class or classes for which a meeting has been called, represented in person or by proxy, will constitute a quorum unless any action by the unitholders requires approval by holders of a greater percentage of the units, in which case the quorum will be the greater percentage. The units representing the general partner interest are units for distribution and allocation purposes, but do not entitle our general partner to any vote other than its rights as general partner under our partnership agreement, will not be entitled to vote on any action required or permitted to be taken by the unitholders and will not count toward or be considered outstanding when calculating required votes, determining the presence of a quorum, or for similar purposes.

Each record holder of a unit has a vote according to its percentage interest in us, although additional limited partner interests having special voting rights could be issued. Please read “—Issuance of Additional Partnership Interests.” However, if at any time any person or group, other than our general partner and its affiliates, or a direct or subsequently approved transferee of our general partner or its affiliates, acquires, in the aggregate, beneficial ownership of 20.0% or more of any class of units then outstanding, that person or group will lose voting rights on all of its units and the units may not be voted on any matter and will not be considered to be outstanding when sending notices of a meeting of unitholders, calculating required votes, determining the presence of a quorum or for other similar purposes. Common units held in nominee or street name account will be voted by the broker or other nominee in accordance with the instruction of the beneficial owner unless the arrangement between the beneficial owner and its nominee provides otherwise.

Any notice, demand, request, report or proxy material required or permitted to be given or made to record holders of common units under our partnership agreement will be delivered to the record holder by us or by the transfer agent.

Status as Limited Partner

By transfer of common units in accordance with our partnership agreement, each transferee of common units will be admitted as a limited partner with respect to the common units transferred when such transfer and admission are reflected in our books and records. Except as described above under “—Limited Liability,” the common units will be fully paid, and unitholders will not be required to make additional contributions.

Redemption of Ineligible Holders

In order to avoid any material adverse effect on the maximum applicable rates that can be charged to customers by our subsidiaries on assets that may be subject to rate regulation by the Federal Energy Regulatory Commission or an analogous regulatory body in the future, each transferee of common units, upon becoming the record holder of such common units, will automatically certify, and the general partner at any time can request such unitholder to re-certify:

36

Furthermore, in order to avoid a substantial risk of cancellation or forfeiture of any property, including any governmental permit, endorsement or other authorization, in which we have an interest as the result of any federal, state or local law or regulation concerning the nationality, citizenship or other related status of any unitholder, our general partner may at any time request unitholders to certify as to, or provide other information with respect to, their nationality, citizenship or other related status.

The certifications as to taxpayer status and nationality, citizenship or other related status can be changed in any manner our general partner determines is necessary or appropriate to implement its original purpose.

If a unitholder fails to furnish the certification or other requested information with 30 days or if our general partner determines, with the advice of counsel, upon review of such certification or other information that a unitholder does not meet the status set forth in the certification, we will have the right to redeem all of the units held by such unitholder at the market price as of the date three days before the date the notice of redemption is mailed.

The purchase price will be paid in cash or by delivery of a promissory note, as determined by our general partner. Any such promissory note will bear interest at the rate of 5.0% annually and be payable in three equal annual installments of principal and accrued interest, commencing one year after the redemption date. Further, the units will not be entitled to any allocations of income or loss, distributions or voting rights while held by such unitholder.

Indemnification

Under our partnership agreement we will indemnify the following persons, in most circumstances, to the fullest extent permitted by law, from and against all losses, claims, damages or similar events:

Any indemnification under these provisions will only be out of our assets. Unless it otherwise agrees, our general partner will not be personally liable for, or have any obligation to contribute or lend funds or assets to us to enable us to effectuate, indemnification. We may purchase insurance against liabilities asserted against and expenses incurred by persons for our activities, regardless of whether we would have the power to indemnify the person against liabilities under our partnership agreement.

Reimbursement of Expenses

Our partnership agreement requires us to reimburse our general partner for all direct and indirect expenses it incurs or payments it makes on our behalf and all other expenses allocable to us or otherwise incurred by our

37

general partner in connection with operating our business. These expenses include salary, bonus, incentive compensation and other amounts paid to persons who perform services for us or on our behalf and expenses allocated to our general partner by its affiliates. Our general partner is entitled to determine in good faith the expenses that are allocable to us.

Books and Reports

Our general partner is required to keep or cause to be kept appropriate books and records of our business at our principal offices. The books will be maintained for both tax and financial reporting purposes on an accrual basis. For fiscal and tax reporting purposes, we use the calendar year.

We will furnish or make available to record holders of common units, within 105 days after the close of each fiscal year, an annual report containing audited financial statements and a report on those financial statements by our independent public accountants, including a balance sheet and statements of operations and our equity and cash flows. Except for our fourth quarter, we will also furnish or make available summary financial information within 50 days after the close of each quarter. We will be deemed to have made any such report available if we file such report with the SEC on the Electronic Data Gathering, Analysis and Retrieval system (“EDGAR”) or make the report available on a publicly available website that we maintain.

We will furnish each record holder with information reasonably required for federal and state tax reporting purposes within 90 days after the close of each calendar year. This information is expected to be furnished in summary form so that some complex calculations normally required of partners can be avoided. Our ability to furnish this summary information to unitholders will depend on the cooperation of unitholders in supplying us with specific information. Every unitholder will receive information to assist him in determining its federal and state tax liability and filing its federal and state income tax returns, regardless of whether he supplies us with the necessary information.

Right to Inspect Our Books and Records

Our partnership agreement provides that a limited partner can, for a purpose reasonably related to its interest as a limited partner, upon reasonable written demand stating the purpose of such demand and at its own expense, have furnished to him:

Our general partner may, and intends to, keep confidential from the limited partners any information that our general partner reasonably believes to be in the nature of trade secrets or other information the disclosure of which our general partner in good faith believes is not in our best interests or could damage us or our business or that we are required by law or by agreements with third parties to keep confidential. Our partnership agreement limits the right to information that a limited partner would otherwise have under Delaware law.

Registration Rights

Under our partnership agreement, we have agreed to register for resale under the Securities Act of 1933, as amended (“Securities Act”), and applicable state securities laws any common units or other partnership interests proposed to be sold by our general partner or any of its affiliates, other than individuals, or their assignees if an exemption from the registration requirements is not otherwise available. These registration rights continue for two years following any withdrawal or removal of Summit Midstream GP, LLC as our general partner. We are obligated to pay all expenses incidental to the registration, excluding underwriting discounts and commissions.

38

Operating Agreement of Summit Midstream Holdings, LLC

We conduct all of our operations through Summit Holdings and its operating subsidiaries. Under the amended and restated limited liability company agreement of Summit Holdings, the management of Summit Holdings is vested in us. As the sole member, we have the authority to cause Summit Holdings to make distributions to us, among other things, as required.

39

MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES

This section is a summary of the material tax considerations that may be relevant to prospective unitholders who are individual citizens or residents of the United States and, unless otherwise noted in the following discussion, is the opinion of Baker Botts L.L.P., counsel to our general partner and us, insofar as it relates to legal conclusions with respect to matters of U.S. federal income tax law. This section is based upon current provisions of the Internal Revenue Code of 1986, as amended (the “Code”), existing and proposed Treasury regulations promulgated under the Code (the “Treasury Regulations”) and current administrative rulings and court decisions, all of which are subject to change. Later changes in these authorities may cause the tax consequences to vary substantially from the consequences described below. Unless the context otherwise requires, references in this section to “us” or “we” are references to Summit Midstream Partners, LP and our operating subsidiaries.

The following discussion does not comment on all federal income tax matters affecting us or our unitholders. Moreover, the discussion focuses on unitholders who are individual citizens or residents of the U.S. and has only limited application to corporations, estates, entities treated as partnerships for U.S. federal income tax purposes, trusts, nonresident aliens, U.S. expatriates and former citizens or long-term residents of the United States or other unitholders subject to specialized tax treatment, such as banks, insurance companies and other financial institutions, tax-exempt institutions, foreign persons (including, without limitation, controlled foreign corporations, passive foreign investment companies and non-U.S. persons eligible for the benefits of an applicable income tax treaty with the U.S.), IRAs, real estate investment trusts (REITs) or mutual funds, dealers in securities or currencies, traders in securities, U.S. persons whose “functional currency” is not the U.S. dollar, persons holding their units as part of a “straddle,” “hedge,” “conversion transaction” or other risk reduction transaction, and persons deemed to sell their units under the constructive sale provisions of the Code. In addition, the discussion only comments to a limited extent on state, local and foreign tax consequences. Accordingly, we encourage each prospective unitholder to consult his own tax advisor in analyzing the state, local and foreign tax consequences particular to him of the ownership or disposition of units and potential changes in applicable tax laws.

All statements as to matters of federal income tax law and legal conclusions with respect thereto, but not as to factual matters, contained in this section, unless otherwise noted, are the opinion of Baker Botts L.L.P. and are based on the accuracy of the representations made by us.

We will rely on opinions of Baker Botts L.L.P. An opinion of counsel represents only that counsel’s best legal judgment and does not bind the IRS or the courts. Accordingly, the opinions and statements made herein may not be sustained by a court if contested by the IRS. Any contest of this sort with the IRS may materially and adversely impact the market for our units and the prices at which our units trade. In addition, the costs of any contest with the IRS, principally legal, accounting and related fees, will result in a reduction in our cash available for distribution and thus will be borne indirectly by our unitholders and our general partner. Additionally, pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, for taxable years beginning after December 31, 2017, if the IRS makes an audit adjustment to any of our income tax returns, our unitholders will directly or indirectly bear any taxes (including any applicable penalties and interest) resulting from such audit adjustment (please read “—Administrative Matters—Information Returns and Audit Procedures”). Furthermore, the tax treatment of us, or of an investment in us, may be significantly modified by future legislative or administrative changes or court decisions. Any modifications may or may not be retroactively applied.

For the reasons described below, Baker Botts L.L.P. has not rendered an opinion with respect to the following specific federal income tax issues: (i) the treatment of a unitholder whose units are loaned to a short seller to cover a short sale of units (please read “—Tax Consequences of Unit Ownership—Treatment of Short Sales”); (ii) whether our monthly convention for allocating taxable income and losses is permitted by existing Treasury Regulations (please read “—Disposition of Units—Allocations Between Transferors and Transferees”) and (iii) whether our method for taking into account Section 743 adjustments is sustainable in certain cases (please read “—Tax Consequences of Unit Ownership—Section 754 Election” and “—Uniformity of Units”).

40

Partnership Status

A partnership is not a taxable entity and incurs no federal income tax liability. Instead, each partner of a partnership is required to take into account his share of items of income, gain, loss and deduction of the partnership in computing his federal income tax liability, regardless of whether cash distributions are made to him by the partnership. Distributions by a partnership to a partner are generally not taxable to the partnership or the partner unless the amount of cash distributed to him is in excess of the partner’s adjusted basis in his partnership interest.

Section 7704 of the Code provides that publicly traded limited partnerships will, as a general rule, be taxed as corporations. However, an exception, referred to as the “Qualifying Income Exception,” exists with respect to publicly traded limited partnerships of which 90% or more of the gross income for every taxable year consists of “qualifying income.” Qualifying income includes income and gains derived from the transportation, processing, storage and marketing of crude oil, natural gas and refined products thereof. Other types of qualifying income include interest (other than from a financial business), dividends, gains from the sale of real property and gains from the sale or other disposition of capital assets held for the production of income that otherwise constitutes qualifying income. We estimate that less than 5% of our current gross income is not qualifying income; however, this estimate could change from time to time. Based upon and subject to this estimate, the factual representations made by us and our general partner and a review of the applicable legal authorities, Baker Botts L.L.P. is of the opinion that at least 90% of our current gross income constitutes qualifying income. The portion of our income that is qualifying income may change from time to time.

The IRS has made no determination as to our status or the status of our operating subsidiaries for federal income tax purposes. Instead, we will rely on the opinion of Baker Botts L.L.P. on such matters. It is the opinion of Baker Botts L.L.P. that, based upon the Code, its regulations, published revenue rulings and court decisions and the representations described below that:

In rendering its opinion, Baker Botts L.L.P. has relied on factual representations made by us and our general partner. The representations made by us and our general partner upon which Baker Botts L.L.P. has relied include:

We believe these representations are true and expect that these representations will continue to be true in the future.

The present federal income tax treatment of publicly traded partnerships or an investment in the units of publicly traded partnerships may be modified by administrative, legislative or judicial interpretation at any time. For example, from time to time, the President and members of the U.S. Congress propose and consider substantive changes to the existing federal income tax laws that affect publicly traded partnerships, such as proposals eliminating the Qualifying Income Exception upon which we rely for our treatment as a partnership for U.S. federal income tax purposes.

In addition, on January 24, 2017, the IRS and the U.S. Treasury Department published in the Federal Register final regulations regarding qualifying income under Section 7704(d)(1)(E) (the “Final Regulations”). The Final

41

Regulations apply to taxable years beginning after January 19, 2017. Under current law and the Final Regulations, we believe that we satisfy the qualifying income requirement for us to be treated as a partnership for U.S. federal income tax purposes. However, there are no assurances that current law or the Final Regulations will not be revised to take a position that is contrary to our interpretation.

If we fail to meet the Qualifying Income Exception, other than a failure that is determined by the IRS to be inadvertent and that is cured within a reasonable time after discovery (in which case the IRS may also require us to make adjustments with respect to our unitholders or pay other amounts), we will be treated as if we had transferred all of our assets, subject to liabilities, to a newly formed corporation, on the first day of the year in which we fail to meet the Qualifying Income Exception, in return for stock in that corporation, and then distributed that stock to the unitholders in liquidation of their interests in us. This deemed contribution and liquidation should be tax-free to unitholders and us so long as we, at that time, do not have liabilities in excess of the tax basis of our assets. Thereafter, we would be treated as a corporation for federal income tax purposes.

If we were treated as an association taxable as a corporation in any taxable year, either as a result of a failure to meet the Qualifying Income Exception or otherwise, our items of income, gain, loss and deduction would be reflected only on our tax return rather than being passed through to our unitholders, and our net income would be taxed to us at corporate rates. In addition, any distribution made to a unitholder would be treated as taxable dividend income, to the extent of our current and accumulated earnings and profits, or, in the absence of earnings and profits, a nontaxable return of capital, to the extent of the unitholder’s tax basis in his units, or taxable capital gain, after the unitholder’s tax basis in his units is reduced to zero. Accordingly, taxation as a corporation would result in a material reduction in a unitholder’s cash flow and after-tax return and thus would likely result in a substantial reduction of the value of the units.

The discussion below is based on Baker Botts L.L.P.’s opinion that we will be classified as a partnership for federal income tax purposes.

Limited Partner Status

Unitholders who are admitted as limited partners of Summit Midstream Partners, LP will be treated as partners of Summit Midstream Partners, LP for federal income tax purposes. Also, unitholders whose units are held in street name or by a nominee and who have the right to direct the nominee in the exercise of all substantive rights attendant to the ownership of their units will be treated as partners of Summit Midstream Partners, LP for federal income tax purposes.

A beneficial owner of units whose units have been transferred to a short seller to complete a short sale would appear to lose his status as a partner with respect to those units for federal income tax purposes. Please read “—Tax Consequences of Unit Ownership—Treatment of Short Sales.”

Income, gains, losses or deductions would not appear to be reportable by a unitholder who is not a partner for federal income tax purposes, and any cash distributions received by a unitholder who is not a partner for federal income tax purposes would therefore appear to be fully taxable as ordinary income. These holders are urged to consult their tax advisors with respect to the tax consequences to them of holding units in Summit Midstream Partners, LP. The references to “unitholders” in the discussion that follows are to persons who are treated as partners in Summit Midstream Partners, LP for federal income tax purposes.

Tax Consequences of Unit Ownership

Flow-Through of Taxable Income

Subject to the discussion below under “—Tax Consequences of Unit Ownership—Entity-Level Collections” and “—Administrative Matters—Information Returns and Audit Procedures,” we will not pay any federal income tax. Instead, each unitholder will be required to report on his income tax return his share of our income, gains,

42

losses and deductions without regard to whether we make cash distributions to him. Consequently, we may allocate income to a unitholder even if he has not received a cash distribution. The income we allocate to unitholders will generally be taxable as ordinary income. Each unitholder will be required to include in income his allocable share of our income, gains, losses and deductions for our taxable year ending with or within his taxable year. Our taxable year ends on December 31.

Treatment of Distributions

Distributions by us to a unitholder generally will not be taxable to the unitholder for federal income tax purposes, except to the extent the amount of any such cash distribution exceeds his tax basis in his units immediately before the distribution. Our cash distributions in excess of a unitholder’s tax basis generally will be considered to be gain from the sale or exchange of the units, taxable in accordance with the rules described under “—Disposition of Units.” Any reduction in a unitholder’s share of our liabilities for which no partner, including the general partner, bears the economic risk of loss, known as “nonrecourse liabilities,” will be treated as a distribution by us of cash to that unitholder. To the extent our distributions cause a unitholder’s “at-risk” amount to be less than zero at the end of any taxable year, he must recapture any losses deducted in previous years. Please read “—Tax Consequences of Unit Ownership—Limitations on Deductibility of Losses.”

A decrease in a unitholder’s percentage interest in us because of our issuance of additional units will decrease his share of our nonrecourse liabilities, and thus will result in a corresponding deemed distribution of cash. This deemed distribution may constitute a non-pro rata distribution. A non-pro rata distribution of money or property may result in ordinary income to a unitholder, regardless of his tax basis in his units, if the distribution reduces the unitholder’s share of our “unrealized receivables,” including depreciation recapture and/or substantially appreciated “inventory items,” each as defined in the Code, and collectively, “Section 751 Assets.” To that extent, the unitholder will be treated as having been distributed his proportionate share of the Section 751 Assets and then having exchanged those assets with us in return for the non-pro rata portion of the actual distribution made to him. This latter deemed exchange will generally result in the unitholder’s realization of ordinary income, which will equal the excess of (i) the non-pro rata portion of that distribution over (ii) the unitholder’s tax basis (generally zero) for the share of Section 751 Assets deemed relinquished in the exchange.

Basis of Units

A unitholder’s initial tax basis for his units will be the amount he paid for the units plus his share of our nonrecourse liabilities. That basis will be increased by his share of our income and by any increases in his share of our nonrecourse liabilities. That basis will be decreased, but not below zero, by distributions from us, by the unitholder’s share of our losses, by any decreases in his share of our nonrecourse liabilities and by his share of our expenditures that are not deductible in computing taxable income and are not required to be capitalized. A unitholder will have no share of our debt that is recourse to our general partner to the extent of the general partner’s “net value” as defined in Treasury Regulations under Section 752 of the Code, but will have a share, generally based on his share of profits, of our nonrecourse liabilities. Please read “—Disposition of Units—Recognition of Gain or Loss.”

Limitations on Deductibility of Losses

The deduction by a unitholder of his share of our losses will be limited to the tax basis in his units and, in the case of an individual unitholder, estate, trust, or corporate unitholder (if more than 50% of the value of the corporate unitholder’s stock is owned directly or indirectly by or for five or fewer individuals or some tax-exempt organizations) to the amount for which the unitholder is considered to be “at risk” with respect to our activities, if that is less than his tax basis. A unitholder subject to these limitations must recapture losses deducted in previous years to the extent that distributions cause his at-risk amount to be less than zero at the end of any taxable year. Losses disallowed to a unitholder or recaptured as a result of these limitations will carry forward and will be allowable as a deduction to the extent that his at-risk amount is subsequently increased, provided

43

such losses do not exceed such unitholder’s tax basis in his units. Upon the taxable disposition of a unit, any gain recognized by a unitholder can be offset by losses that were previously suspended by the at-risk limitation but may not be offset by losses suspended by the basis limitation. Any loss previously suspended by the at-risk limitation in excess of that gain would no longer be utilizable.

In general, a unitholder will be at risk to the extent of the tax basis of his units, excluding any portion of that basis attributable to his share of our nonrecourse liabilities, reduced by (i) any portion of that basis representing amounts otherwise protected against loss because of a guarantee, stop loss agreement or other similar arrangement and (ii) any amount of money he borrows to acquire or hold his units, if the lender of those borrowed funds owns an interest in us, is related to the unitholder or can look only to the units for repayment. A unitholder’s at-risk amount will increase or decrease as the tax basis of the unitholder’s units increases or decreases, other than tax basis increases or decreases attributable to increases or decreases in his share of our nonrecourse liabilities.

In addition to the basis and at-risk limitations on the deductibility of losses, the passive loss limitations generally provide that individuals, estates, trusts and some closely-held corporations and personal service corporations can deduct losses from passive activities, which are generally trade or business activities in which the taxpayer does not materially participate, only to the extent of the taxpayer’s income from those passive activities. The passive loss limitations are applied separately with respect to each publicly traded limited partnership. Consequently, any passive losses we generate will only be available to offset our passive income generated in the future and will not be available to offset income from other passive activities or investments, including our investments or a unitholder’s investments in other publicly traded limited partnerships, or the unitholder’s salary, active business or other income. Passive losses that are not deductible because they exceed a unitholder’s share of income we generate may be deducted in full when he disposes of his entire investment in us in a fully taxable transaction with an unrelated party. The passive loss limitations are applied after other applicable limitations on deductions, including the at-risk rules and the basis limitation.

A unitholder’s share of our net income may be offset by any of our suspended passive losses, but it may not be offset by any other current or carryover losses from other passive activities, including those attributable to other publicly traded limited partnerships.

Limitations on Interest Deductions

The deductibility of a non-corporate taxpayer’s “investment interest expense” is generally limited to the amount of that taxpayer’s “net investment income.” Investment interest expense includes:

The computation of a unitholder’s investment interest expense will take into account interest on any margin account borrowing or other loan incurred to purchase or carry a unit. Net investment income includes gross income from property held for investment and amounts treated as portfolio income under the passive loss rules, less deductible expenses, other than interest, directly connected with the production of investment income, but generally does not include gains attributable to the disposition of property held for investment or (if applicable) qualified dividend income. The IRS has indicated that the net passive income earned by a publicly traded limited partnership will be treated as investment income to its unitholders. In addition, the unitholder’s share of our portfolio income will be treated as investment income.

Recently proposed legislation would disallow a deduction for our interest expense for interest in excess of a percentage of our adjusted taxable income. We are unable to predict whether this change or other proposals will ultimately be enacted, but any such changes could limit the interest expense deduction available to our unitholders.

44

Entity-Level Collections

If we are required or elect under applicable law to pay any federal, state, local or foreign income tax on behalf of any unitholder or our general partner or any former unitholder, we are authorized to pay those taxes from our funds. That payment, if made, will be treated as a distribution of cash to the unitholder on whose behalf the payment was made. If the payment is made on behalf of a person whose identity cannot be determined, we are authorized to treat the payment as a distribution to all current unitholders. We are authorized to amend our partnership agreement in the manner necessary to maintain uniformity of intrinsic tax characteristics of units and to adjust later distributions, so that after giving effect to these distributions, the priority and characterization of distributions otherwise applicable under our partnership agreement is maintained as nearly as is practicable. Payments by us as described above could give rise to an overpayment of tax on behalf of an individual unitholder in which event the unitholder would be required to file a claim in order to obtain a credit or refund.

Allocation of Income, Gain, Loss and Deduction

In general, if we have a net profit, our items of income, gain, loss and deduction will be allocated among our general partner and the unitholders in accordance with their percentage interests in us. At any time that incentive distributions are made to our general partner, gross income will be allocated to our general partner to the extent of these distributions. If we have a net loss, that loss will be allocated first to our general partner and the unitholders in accordance with their percentage interests in us to the extent of their positive capital accounts, as adjusted to take into account the unitholders’ share of nonrecourse debt, and, second, to our general partner.

Section 704(c) of the Code and related Treasury Regulations require us to adjust the “book” basis of all assets held by us prior to an issuance of additional units to equal their fair market values at the time of a unit issuance. Purchasers of units in an offering are entitled to calculate tax depreciation and amortization deductions and other relevant tax items with respect to our assets based upon that “book” basis, which effectively puts purchasers in that offering in the same position as if our assets had a tax basis equal to their fair market value at the time of unit issuance. This may have the effect of decreasing the amount of our tax depreciation or amortization deductions thereafter allocated to purchasers of units in an earlier offering or of requiring purchasers of units in an earlier offering to thereafter recognize “remedial income” rather than depreciation and amortization deductions. In this context, we use the term “book” as that term is used in Treasury Regulations under Section 704 of the Code. The “book” basis assigned to our assets for this purpose may not be the same as the book value of our property for financial reporting purposes.

In addition, items of recapture income will be allocated to the extent possible to the unitholder who was allocated the deduction giving rise to the treatment of that gain as recapture income in order to minimize the recognition of ordinary income by some unitholders. Finally, although we do not expect that our operations will result in the creation of negative capital accounts, if negative capital accounts nevertheless result, items of our income and gain will be allocated in an amount and manner sufficient to eliminate the negative balance as quickly as possible.

An allocation of items of our income, gain, loss or deduction, other than an allocation required under the Section 704(c) principles described above, will generally be given effect for federal income tax purposes in determining a partner’s share of an item of income, gain, loss or deduction only if the allocation has “substantial economic effect.” In any other case, a partner’s share of an item will be determined on the basis of his interest in us, which will be determined by taking into account all the facts and circumstances, including:

45

Baker Botts L.L.P. is of the opinion that, with the exception of the issues described in “—Tax Consequences of Unit Ownership—Section 754 Election” and “—Disposition of Units—Allocations Between Transferors and Transferees,” and “—Uniformity of Units,” allocations under our partnership agreement will be given effect for federal income tax purposes in determining a partner’s share of an item of income, gain, loss or deduction.

Treatment of Short Sales

A unitholder whose units are loaned to a “short seller” to cover a short sale of units may be considered as having disposed of those units. If so, he would no longer be treated for tax purposes as a partner with respect to those units during the period of the loan and may recognize gain or loss from the disposition. As a result, during this period:

Because there is no direct or indirect controlling authority on the issue relating to partnership interests, Baker Botts L.L.P. has not rendered an opinion regarding the tax treatment of a unitholder whose units are loaned to a short seller to cover a short sale of units; therefore, unitholders desiring to assure their status as partners and avoid the risk of gain recognition from a loan to a short seller are urged to consult a tax advisor to discuss whether it is advisable to modify any applicable brokerage account agreements to prohibit their brokers from borrowing and loaning their units. The IRS has previously announced that it is studying issues relating to the tax treatment of short sales of partnership interests. Please read “—Disposition of Units—Recognition of Gain or Loss.”

Alternative Minimum Tax

Each unitholder will be required to take into account his distributive share of any items of our income, gain, loss or deduction for purposes of the alternative minimum tax. The minimum tax rate for non-corporate married taxpayers filing jointly in 2017 is 26% on the first $187,800 of alternative minimum taxable income in excess of the exemption amount and 28% on any additional alternative minimum taxable income. Prospective unitholders are urged to consult with their tax advisors as to the impact of an investment in units on their liability for the alternative minimum tax.

Tax Rates

The highest marginal U.S. federal income tax rate applicable to ordinary income of individuals is 39.6% and the highest marginal U.S. federal income tax rate applicable to long-term capital gains (generally, capital gains on certain assets held for more than twelve months) of individuals is 20%. Such rates are subject to change by new legislation at any time.

In addition, a 3.8% Medicare tax, or NIIT, applies to certain net investment income earned by individuals, estates and trusts. For these purposes, net investment income generally includes a unitholder’s allocable share of our income and gain realized by a unitholder from a sale of units. In the case of an individual, the tax is imposed on the lesser of (i) the unitholder’s net investment income and (ii) the amount by which the unitholder’s modified adjusted gross income exceeds $250,000 (if the unitholder is married and filing jointly or a surviving spouse), $125,000 (if the unitholder is married and filing separately) or $200,000 (in any other case). In the case of an estate or trust, the tax is imposed on the lesser of (i) undistributed net investment income and (ii) the excess adjusted gross income over the dollar amount at which the highest income tax bracket applicable to an estate or trust begins.

46

Section 754 Election

We have made an election permitted by Section 754 of the Code. That election is irrevocable without the consent of the IRS unless there is a constructive termination of the partnership. Please read “—Disposition of Units—Constructive Termination.” The election will generally permit us to adjust a unit purchaser’s tax basis in our assets (“inside basis”) under Section 743(b) of the Code to reflect his purchase price. This election does not apply with respect to a person who purchases units directly from us. The Section 743(b) adjustment belongs to the purchaser and not to other unitholders. For purposes of this discussion, the inside basis in our assets with respect to a unitholder will be considered to have two components: (i) his share of our tax basis in our assets, or common basis, and (ii) his Section 743(b) adjustment to that basis.

The timing of deductions attributable to a Section 743(b) adjustment to our common basis will depend upon a number of factors, including the nature of the assets to which the adjustment is allocable, the extent to which the adjustment offsets any Section 704(c) type gain or loss with respect to an asset and certain elections we make as to the manner in which we apply Section 704(c) principles with respect to an asset with respect to which the adjustment is allocable. Please read “—Tax Consequences of Unit Ownership—Allocation of Income, Gain, Loss and Deduction.” The timing of these deductions may affect the uniformity of our units. Please read “—Uniformity of Units.”

A Section 754 election is advantageous if the transferee’s tax basis in his units is higher than the units’ share of the aggregate tax basis of our assets immediately prior to the transfer. In that case, as a result of the election, the transferee would have, among other items, a greater amount of depreciation deductions and his share of any gain or loss on a sale of our assets would be less. Conversely, a Section 754 election is disadvantageous if the transferee’s tax basis in his units is lower than those units’ share of the aggregate tax basis of our assets immediately prior to the transfer. Thus, the fair market value of the units may be affected either favorably or unfavorably by the election. A basis adjustment is required regardless of whether a Section 754 election is made in the case of a transfer of an interest in us if we have a substantial built-in loss immediately after the transfer, or if we distribute property and have a substantial basis reduction. Generally a built-in loss or a basis reduction is substantial if it exceeds $250,000.

The calculations involved in the Section 754 election are complex and will be made on the basis of assumptions as to the value of our assets and other matters. For example, the allocation of the Section 743(b) adjustment among our assets must be made in accordance with the Code. The IRS could seek to reallocate some or all of any Section 743(b) adjustment allocated by us to our tangible assets to goodwill instead. Goodwill, as an intangible asset, is generally nonamortizable or amortizable over a longer period of time or under a less accelerated method than our tangible assets. We cannot assure you that the determinations we make will not be successfully challenged by the IRS and that the deductions resulting from them will not be reduced or disallowed altogether. Should the IRS require a different basis adjustment to be made, and should, in our opinion, the expense of compliance exceed the benefit of the election, we may seek permission from the IRS to revoke our Section 754 election. If permission is granted, a subsequent purchaser of units may be allocated more income than he would have been allocated had the election not been revoked.

Tax Treatment of Operations

Accounting Method and Taxable Year

We use the year ending December 31 as our taxable year and the accrual method of accounting for federal income tax purposes. Each unitholder will be required to include in income his share of our income, gain, loss and deduction for our taxable year ending within or with his taxable year. In addition, a unitholder who has a taxable year ending on a date other than December 31 and who disposes of all of his units following the close of our taxable year but before the close of his taxable year must include his share of our income, gain, loss and deduction in income for his taxable year, with the result that he will be required to include in income for his taxable year his share of more than twelve months of our income, gain, loss and deduction. Please read “—Disposition of Units—Allocations Between Transferors and Transferees.”

47

Tax Basis, Depreciation and Amortization

The tax basis of our assets will be used for purposes of computing depreciation and cost recovery deductions and, ultimately, gain or loss on the disposition of these assets. The federal income tax burden associated with the difference between the fair market value of our assets and their tax basis immediately prior to an offering will be borne by our general partner and all of our unitholders as of that time. Please read “—Tax Consequences of Unit Ownership—Allocation of Income, Gain, Loss and Deduction.”

To the extent allowable, we may elect to use the depreciation and cost recovery methods, including bonus depreciation to the extent available, that will result in the largest deductions being taken in the early years after assets subject to these allowances are placed in service. Part of or all of the goodwill, going concern value and other intangible assets we have acquired or will acquire in connection with an offering may not produce any amortization deductions because of the application of the anti-churning restrictions of Section 197 of the Code. Please read “—Uniformity of Units.” Property we subsequently acquire or construct may be depreciated using accelerated methods permitted by the Code.

If we dispose of depreciable property by sale, foreclosure or otherwise, all or a portion of any gain, determined by reference to the amount of depreciation previously deducted and the nature of the property, may be subject to the recapture rules and taxed as ordinary income rather than capital gain. Similarly, a unitholder who has taken cost recovery or depreciation deductions with respect to property we own will likely be required to recapture some or all of those deductions as ordinary income upon a sale of his interest in us. Please read “—Tax Consequences of Unit Ownership—Allocation of Income, Gain, Loss and Deduction” and “—Disposition of Units—Recognition of Gain or Loss.”

The costs we incur in selling our units (called “syndication expenses”) must be capitalized and cannot be deducted currently, ratably or upon our termination. There are uncertainties regarding the classification of costs as organization expenses, which may be amortized by us, and as syndication expenses, which may not be amortized by us. The underwriting discounts and commissions we incur will be treated as syndication expenses.

Valuation and Tax Basis of Our Properties

The federal income tax consequences of the ownership and disposition of units will depend in part on our estimates of the relative fair market values, and the initial tax bases, of our assets. Although we may from time to time consult with professional appraisers regarding valuation matters, we will make many of the relative fair market value estimates ourselves. These estimates and determinations of basis are subject to challenge and will not be binding on the IRS or the courts. If the estimates of fair market value or basis are later found to be incorrect, the character and amount of items of income, gain, loss or deductions previously reported by unitholders might change, and unitholders might be required to adjust their tax liability for prior years and incur interest and penalties with respect to those adjustments.

Disposition of Units

Recognition of Gain or Loss

Gain or loss will be recognized on a sale of units equal to the difference between the amount realized and the unitholder’s tax basis for the units sold. A unitholder’s amount realized will be measured by the sum of the cash or the fair market value of other property received by him plus his share of our nonrecourse liabilities. Because the amount realized includes a unitholder’s share of our nonrecourse liabilities, the gain recognized on the sale of units could result in a tax liability in excess of any cash received from the sale.

Prior distributions from us that in the aggregate were in excess of cumulative net taxable income for a unit and, therefore, decreased a unitholder’s tax basis in that unit will, in effect, become taxable income if the unit is sold at a price greater than the unitholder’s tax basis in that unit, even if the price received is less than his original cost.

48

Except as noted below, gain or loss recognized by a unitholder, other than a “dealer” in units, on the sale or exchange of a unit will generally be taxable as capital gain or loss. Capital gain recognized by an individual on the sale of units held for more than twelve months will generally be taxed at the U.S. federal income tax rate applicable to long-term capital gains. However, a portion of this gain or loss, which will likely be substantial, will be separately computed and taxed as ordinary income or loss under Section 751 of the Code to the extent attributable to assets giving rise to depreciation recapture or other “unrealized receivables” or to “inventory items” we own. The term “unrealized receivables” includes potential recapture items, including depreciation recapture. Ordinary income attributable to unrealized receivables, inventory items and depreciation recapture may exceed net taxable gain realized upon the sale of a unit and may be recognized even if there is a net taxable loss realized on the sale of a unit. Thus, a unitholder may recognize both ordinary income and a capital loss upon a sale of units. Capital losses may offset capital gains and no more than $3,000 of ordinary income, in the case of individuals, and may only be used to offset capital gains in the case of corporations. Both ordinary income and capital gain recognized on a sale of units may be subject to the NIIT in certain circumstances. Please read “—Tax Consequences of Unit Ownership—Tax Rates.”

The IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all those interests. Upon a sale or other disposition of less than all of those interests, a portion of that tax basis must be allocated to the interests sold using an “equitable apportionment” method, which generally means that the tax basis allocated to the interest sold equals an amount that bears the same relation to the partner’s tax basis in his entire interest in the partnership as the value of the interest sold bears to the value of the partner’s entire interest in the partnership. Treasury Regulations under Section 1223 of the Code allow a selling unitholder who can identify units transferred with an ascertainable holding period to elect to use the actual holding period of the units transferred. Thus, according to the ruling discussed above, a unitholder will be unable to select high or low basis units to sell as would be the case with corporate stock, but, according to the Treasury Regulations, he may designate specific units sold for purposes of determining the holding period of units transferred. A unitholder electing to use the actual holding period of units transferred must consistently use that identification method for all subsequent sales or exchanges of units. A unitholder considering the purchase of additional units or a sale of units purchased in separate transactions is urged to consult his tax advisor as to the possible consequences of this ruling and application of the Treasury Regulations.

Specific provisions of the Code affect the taxation of some financial products and securities, including partnership interests, by treating a taxpayer as having sold an “appreciated” partnership interest, one in which gain would be recognized if it were sold, assigned or terminated at its fair market value, if the taxpayer or related persons enter(s) into:

in each case, with respect to the partnership interest or substantially identical property.

Moreover, if a taxpayer has previously entered into a short sale, an offsetting notional principal contract or a futures or forward contract with respect to the partnership interest, the taxpayer will be treated as having sold that position if the taxpayer or a related person then acquires the partnership interest or substantially identical property. The Secretary of the Treasury is also authorized to issue regulations that treat a taxpayer that enters into transactions or positions that have substantially the same effect as the preceding transactions as having constructively sold the financial position.

Allocations Between Transferors and Transferees

In general, our taxable income or loss will be determined annually, will be prorated on a monthly basis and will be subsequently apportioned among the unitholders in proportion to the number of units owned by each of them

49

as of the opening of the applicable exchange on the first business day of the month, which we refer to in this prospectus as the “Allocation Date.” However, gain or loss realized on a sale or other disposition of our assets or, in the discretion of the general partner, any other extraordinary item of income, gain, loss or deduction will be allocated among the unitholders on the Allocation Date in the month in which such income, gain, loss or deduction is recognized. As a result, a unitholder transferring units may be allocated income, gain, loss and deduction realized after the date of transfer.

Simplifying conventions are contemplated by the Code and most publicly traded partnerships use similar simplifying conventions. The U.S. Treasury Department and the IRS adopted final Treasury Regulations allowing a similar monthly simplifying convention. However, the final regulations do not specifically authorize all aspects of the proration method we have currently adopted. Accordingly, Baker Botts L.L.P. is unable to opine on the validity of this method of allocating income and deductions between transferee and transferor unitholders. If the IRS takes the position that this method is not allowed under the final Treasury Regulations, or only applies to transfers of less than all of the unitholder’s interest, our taxable income or losses could be reallocated among our unitholders. We are authorized to revise our method of allocation between transferee and transferor unitholders, as well as among unitholders whose interests vary during a taxable year, to conform to a method permitted under future Treasury Regulations.

A unitholder who disposes of units prior to the record date set for a cash distribution for that quarter will be allocated items of our income, gain, loss and deduction attributable to the month of disposition but will not be entitled to receive a cash distribution for that period.

Notification Requirements

A unitholder who sells any of his units is generally required to notify us in writing of that sale within 30 days after the sale (or, if earlier, January 15 of the year following the sale). A purchaser of units who purchases units from another unitholder is also generally required to notify us in writing of that purchase within 30 days after the purchase. Upon receiving such notifications, we are required to notify the IRS of that transaction and to furnish specified information to the transferor and transferee. Failure to notify us of a purchase may, in some cases, lead to the imposition of penalties. However, these reporting requirements do not apply to a sale by an individual who is a citizen of the U.S. and who effects the sale or exchange through a broker who will satisfy such requirements.

Constructive Termination

We will be considered to have technically terminated our partnership for federal income tax purposes if there is a sale or exchange of 50% or more of the total interests in our capital and profits within a twelve-month period. For purposes of determining whether the 50% threshold has been met, multiple sales of the same interest will be counted only once. Our technical termination would, among other things, result in the closing of our taxable year for all unitholders, which would result in us filing two tax returns (and our unitholders could receive two schedules K-1 if relief was not available, as described below) for one fiscal year and could result in a deferral of depreciation deductions allowable in computing our taxable income. A sale or exchange of 50% or more of the total interests in the capital and profits of any entity in which we own an interest that is treated as a partnership for federal income tax purposes within a twelve-month period will result in a technical termination of such entity and could also result in a deferral of depreciation deductions allowable in computing our taxable income. In the case of a unitholder reporting on a taxable year other than a fiscal year ending December 31, the closing of our taxable year caused by our technical termination may also result in more than twelve months of our taxable income or loss being includable in his taxable income for the year of termination. Our termination currently would not affect our classification as a partnership for federal income tax purposes, but instead we would be treated as a new partnership for federal income tax purposes. If treated as a new partnership, we must make new tax elections, including a new election under Section 754 of the Code, and could be subject to penalties if we are unable to determine that a termination occurred. The IRS has recently announced a publicly traded limited partnership technical termination relief program whereby, if a publicly traded limited partnership that technically

50

terminated requests publicly traded limited partnership technical termination relief and such relief is granted by the IRS, among other things, the partnership will only have to provide one Schedule K-1 to unitholders for the year notwithstanding two partnership tax years.

Uniformity of Units

Because we cannot match transferors and transferees of units, we must maintain uniformity of the economic and tax characteristics of the units to a purchaser of these units. In the absence of uniformity, we may be unable to completely comply with a number of federal income tax requirements, both statutory and regulatory. Any non-uniformity could have an impact upon the value of our units. The timing of deductions attributable to Section 743(b) adjustments to the common basis of our assets with respect to persons purchasing units from another unitholder may affect the uniformity of our units. Please read “—Tax Consequences of Unit Ownership—Section 754 Election.”

For example, some types of depreciable assets are not subject to the typical rules governing depreciation (under Section 168 of the Code) or amortization (under Section 197 of the Code). If we were to acquire any assets of that type, the timing of a unit purchaser’s deductions with respect to Section 743(b) adjustments to the common basis of those assets might differ depending upon when and to whom the unit he purchased was originally issued. We do not currently expect to acquire any assets of that type. However, if we were to acquire a material amount of assets of that type, we intend to adopt tax positions as to those assets that will not result in any such lack of uniformity. Any such tax positions taken by us might result in allocations to some unitholders of smaller depreciation deductions than they would otherwise be entitled to receive. Baker Botts L.L.P. has not rendered an opinion with respect to those types of tax positions. Moreover, the IRS might challenge those tax positions. If we took such a tax position and the IRS successfully challenged the position, the uniformity of our units might be affected, and the gain from the sale of our units might be increased without the benefit of additional deductions. Please read “—Disposition of Units—Recognition of Gain or Loss.”

Tax-Exempt Organizations and Other Investors

Ownership of units by employee benefit plans, other tax-exempt organizations, non-resident aliens, foreign corporations and other foreign persons raises issues unique to those investors and, as described below to a limited extent, may have substantially adverse tax consequences to them. If you are a tax-exempt entity or a non-U.S. person, you should consult your tax advisor before investing in our units. Employee benefit plans and most other organizations exempt from federal income tax, including individual retirement accounts and other retirement plans, are subject to federal income tax on unrelated business taxable income. Virtually all of our income allocated to a unitholder that is a tax-exempt organization will be unrelated business taxable income and will be taxable to it.

Non-resident aliens and foreign corporations, trusts or estates that own units will be considered to be engaged in business in the U.S. because of the ownership of units. As a consequence, they will be required to file federal tax returns to report their share of our income, gain, loss or deduction and pay federal income tax at regular rates on their share of our net income or gain. Moreover, under rules applicable to publicly traded limited partnerships, our quarterly distribution to foreign unitholders will be subject to withholding at the highest applicable effective tax rate. Each foreign unitholder must obtain a taxpayer identification number from the IRS and submit that number to our transfer agent on a Form W-8BEN or applicable substitute form in order to obtain credit for these withholding taxes. A change in applicable law may require us to change these procedures.

In addition, because a foreign corporation that owns units will be treated as engaged in a U.S. trade or business, that corporation may be subject to the U.S. branch profits tax at a rate of 30%, in addition to regular federal income tax, on its share of our earnings and profits, as adjusted for changes in the foreign corporation’s “U.S. net equity,” that is effectively connected with the conduct of a U.S. trade or business. That tax may be reduced or eliminated by an income tax treaty between the U.S. and the country in which the foreign corporate unitholder is

51

a “qualified resident.” In addition, this type of unitholder is subject to special information reporting requirements under Section 6038C of the Code.

A foreign unitholder who sells or otherwise disposes of a unit will be subject to U.S. federal income tax on gain realized from the sale or disposition of that unit to the extent the gain is effectively connected with a U.S. trade or business of the foreign unitholder. Under a ruling published by the IRS, interpreting the scope of “effectively connected income,” a foreign unitholder would be considered to be engaged in a trade or business in the U.S. by virtue of the U.S. activities of the partnership, and part or all of that unitholder’s gain would be effectively connected with that unitholder’s indirect U.S. trade or business. Moreover, under the Foreign Investment in Real Property Tax Act, a foreign unitholder generally will be subject to U.S. federal income tax upon the sale or disposition of a unit if (i) he owned (directly or constructively applying certain attribution rules) more than 5% of our units at any time during the five-year period ending on the date of such disposition and (ii) 50% or more of the fair market value of all of our assets consisted of U.S. real property interests at any time during the shorter of the period during which such unitholder held the units or the five-year period ending on the date of disposition. Currently, more than 50% of our assets consist of U.S. real property interests and we do not expect that to change in the foreseeable future. Therefore, foreign unitholders may be subject to federal income tax on gain from the sale or disposition of their units.

Administrative Matters

Information Returns and Audit Procedures

We intend to furnish to each unitholder, within 90 days after the close of each calendar year, specific tax information, including a Schedule K-1, which describes his share of our income, gain, loss and deduction for our preceding taxable year. In preparing this information, which will not be reviewed by counsel, we will take various accounting and reporting positions, some of which have been mentioned earlier, to determine each unitholder’s share of income, gain, loss and deduction. We cannot assure you that those positions will yield a result that conforms to the requirements of the Code, Treasury Regulations or administrative interpretations of the IRS. Neither we nor Baker Botts L.L.P. can assure prospective unitholders that the IRS will not successfully contend in court that those positions are impermissible. Any challenge by the IRS could negatively affect the value of the units.

The IRS may audit our federal income tax information returns. Adjustments resulting from an IRS audit may require each unitholder to adjust a prior year’s tax liability, and possibly may result in an audit of his return. Any audit of a unitholder’s return could result in adjustments not related to our returns as well as those related to our returns.

Partnerships generally are treated as separate entities for purposes of federal tax audits, judicial review of administrative adjustments by the IRS and tax settlement proceedings. The tax treatment of partnership items of income, gain, loss and deduction are determined in a partnership proceeding rather than in separate proceedings with the partners. The Code requires that one partner be designated as the “Tax Matters Partner” for these purposes. Our partnership agreement names our general partner as our Tax Matters Partner. The Tax Matters Partner will make some elections on our behalf and on behalf of unitholders. In addition, the Tax Matters Partner can extend the statute of limitations for assessment of tax deficiencies against unitholders for items in our returns. The Tax Matters Partner may bind a unitholder with less than a 1% profits interest in us to a settlement with the IRS unless that unitholder elects, by filing a statement with the IRS, not to give that authority to the Tax Matters Partner. The Tax Matters Partner may seek judicial review, by which all the unitholders are bound, of a final partnership administrative adjustment and, if the Tax Matters Partner fails to seek judicial review, judicial review may be sought by any unitholder having at least a 1% interest in profits or by any group of unitholders having in the aggregate at least a 5% interest in profits. However, only one action for judicial review will go forward, and each unitholder with an interest in the outcome may participate.

52

A unitholder must file a statement with the IRS identifying the treatment of any item on his federal income tax return that is not consistent with the treatment of the item on our return. Intentional or negligent disregard of this consistency requirement may subject a unitholder to substantial penalties.

Pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, for taxable years beginning after December 31, 2017, if the IRS makes an audit adjustment to any of our income tax returns, it may assess and collect any taxes (including any applicable penalties and interest) resulting from such audit adjustment directly from us, unless we elect to have our general partner and unitholders take the audit adjustment into account in accordance with their interests in us during the taxable year under audit. Similarly, for such taxable years, if the IRS makes an audit adjustment to an income tax return filed by an entity in which we are a member or partner, it may assess and collect any taxes (including penalties and interest) resulting from such audit adjustment directly from such entity. Generally, we expect to elect to have our general partner and unitholders take any material audit adjustment into account in accordance with their interests in us during the taxable year under audit, but there can be no assurance that such election, if made, will be effective in all circumstances. With respect to an audit adjustment as to an entity in which we are a member or partner, we may not be able to have our general partner and our unitholders take such audit adjustment into account in accordance with their interests in us during the taxable year under audit, and if we are unable to do so, our then current unitholders may bear some or all of the tax liability resulting from such audit adjustment, even if such unitholders did not own our units during the taxable year under audit. If, as a result of any such audit adjustment, we are required to make payments of taxes, penalties, and interest, we may require our unitholders and former unitholders to reimburse us for such taxes (including any applicable penalties or interest) or, if we are required to bear such payment our cash available for distribution to our unitholders might be substantially reduced.

Additionally, pursuant to the Bipartisan Budget Act of 2015, as amended by the Protecting Americans from Tax Hikes Act of 2015, the Code will no longer require that we designate a “tax matters partner” pursuant to Section 6231(a)(7) of the Code (prior to amendment by the Bipartisan Budget Act of 2015). Instead, for taxable years beginning after December 31, 2017, we will be required to designate a partner, or other person, with a substantial presence in the United States as our partnership representative (“Partnership Representative”). The Partnership Representative will have the sole authority to act on our behalf for purposes of, among other things, U.S. federal income tax audits and judicial review of administrative adjustments by the IRS. If we do not make such a designation, the IRS can select any person as the Partnership Representative. We currently anticipate that we will designate our general partner (or one of its affiliates) as the Partnership Representative. Further, any actions taken by us or by the Partnership Representative on our behalf with respect to, among other things, U.S. federal income tax audits and judicial review of administrative adjustments by the IRS, will be binding on us and all of the unitholders.

Additional Withholding Requirements

Withholding taxes may apply to certain types of payments made to “foreign financial institutions” (as specially defined in the Code) and certain other non-U.S. entities. Specifically, a 30% withholding tax may be imposed on interest, dividends and other fixed or determinable annual or periodical gains, profits and income from sources within the U.S. (“FDAP Income”), or gross proceeds from the sale or other disposition of any property of a type which can produce interest or dividends from sources within the U.S. (“Gross Proceeds”) paid to a foreign financial institution or to a “non-financial foreign entity” (as specially defined in the Code), unless (i) the foreign financial institution undertakes certain diligence and reporting, (ii) the non-financial foreign entity either certifies it does not have any substantial U.S. owners or furnishes identifying information regarding each substantial U.S. owner or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. If the payee is a foreign financial institution and is subject to the diligence and reporting requirements in clause (i) above, it must enter into an agreement with the U.S. Treasury requiring, among other things, that it undertake to identify accounts held by certain U.S. persons or U.S.-owned foreign entities, annually report certain information about such accounts, and withhold 30% on payments to noncompliant foreign financial institutions and certain other account holders. An intergovernmental agreement between the United States and an applicable foreign country, or future Treasury Regulations, may modify these requirements.

53

These rules generally apply to payments of FDAP Income currently and will apply to payments of relevant Gross Proceeds from sales or dispositions occurring on or after January 1, 2019. Thus, to the extent we have FDAP Income or will have Gross Proceeds on or after January 1, 2019 that are not treated as effectively connected with a U.S. trade or business (please read “—Tax-Exempt Organizations and Other Investors”), unitholders who are foreign financial institutions or certain other non-US entities may be subject to withholding on distributions they receive from us, or their distributive share of our income, pursuant to the rules described above.

Prospective investors should consult their own tax advisors regarding the potential application of these withholding provisions to their investment in our units.

Nominee Reporting

Persons who hold an interest in us as a nominee for another person are required to furnish to us:

Brokers and financial institutions are required to furnish additional information, including whether they are U.S. persons and specific information on units they acquire, hold or transfer for their own account. A penalty of $250 per failure, up to a maximum of $3.0 million per calendar year, is imposed by the Code for failure to report that information to us. The nominee is required to supply the beneficial owner of the units with the information furnished to us.

Accuracy-Related Penalties

An additional tax equal to 20% of the amount of any portion of an underpayment of tax that is attributable to one or more specified causes, including negligence or disregard of rules or regulations, substantial understatements of income tax and substantial valuation misstatements, is imposed by the Code. No penalty will be imposed, however, for any portion of an underpayment if it is shown that there was a reasonable cause for that portion and that the taxpayer acted in good faith regarding that portion.

For individuals, a substantial understatement of income tax in any taxable year exists if the amount of the understatement exceeds the greater of 10% of the tax required to be shown on the return for the taxable year or $5,000 ($10,000 for most corporations). The amount of any understatement subject to penalty generally is reduced if any portion is attributable to a position adopted on the return:

If any item of income, gain, loss or deduction included in the distributive shares of unitholders might result in that kind of an “understatement” of income for which no “substantial authority” exists, we must disclose the

54

pertinent facts on our return. In addition, we will make a reasonable effort to furnish sufficient information for unitholders to make adequate disclosure on their returns and to take other actions as may be appropriate to permit unitholders to avoid liability for this penalty. More stringent rules apply to “tax shelters,” which we do not believe includes us, or any of our investments, plans or arrangements.

A substantial valuation misstatement exists if (a) the value of any property, or the adjusted basis of any property, claimed on a tax return is 150% or more of the amount determined to be the correct amount of the valuation or adjusted basis, (b) the price for any property or services (or for the use of property) claimed on any such return with respect to any transaction between persons described in Code Section 482 is 200% or more (or 50% or less) of the amount determined under Section 482 to be the correct amount of such price, or (c) the net Code Section 482 transfer price adjustment for the taxable year exceeds the lesser of $5.0 million or 10% of the taxpayer’s gross receipts. No penalty is imposed unless the portion of the underpayment attributable to a substantial valuation misstatement exceeds $5,000 ($10,000 for most corporations). If the valuation claimed on a return is 200% or more than the correct valuation or certain other thresholds are met, the penalty imposed increases to 40%. We do not anticipate making any valuation misstatements.

In addition, the 20% accuracy-related penalty also applies to any portion of an underpayment of tax that is attributable to transactions lacking economic substance. To the extent that such transactions are not disclosed, the penalty imposed is increased to 40%. Additionally, there is no reasonable cause defense to the imposition of this penalty to such transactions.

Reportable Transactions

If we were to engage in a “reportable transaction,” we (and possibly you and others) would be required to make a detailed disclosure of the transaction to the IRS. A transaction may be a reportable transaction based upon any of several factors, including the fact that it is a type of tax avoidance transaction publicly identified by the IRS as a “listed transaction” or that it produces certain kinds of losses for partnerships, individuals, S corporations, and trusts in excess of $2.0 million in any single year, or $4.0 million in any combination of six successive tax years. Our participation in a reportable transaction could increase the likelihood that our federal income tax information return (and possibly your tax return) would be audited by the IRS. Please read “—Administrative Matters—Information Returns and Audit Procedures.”

Moreover, if we were to participate in a reportable transaction with a significant purpose to avoid or evade tax, or in any listed transaction, you may be subject to the following additional consequences:

We do not expect to engage in any “reportable transactions.”

State, Local, Foreign and Other Tax Considerations

In addition to federal income taxes, you likely will be subject to other taxes, such as state, local and foreign income taxes, unincorporated business taxes, and estate, inheritance or intangible taxes that may be imposed by the various jurisdictions in which we do business or own property or in which you are a resident. We currently do business or own property in Colorado, North Dakota, Texas, Utah, Ohio, New Mexico, Wyoming and West Virginia. Several of these states impose a personal income tax on individuals and certain of these states also impose an income tax on corporations and other entities. Moreover, in the future we may also own property or do

55

business in other states that impose income or similar taxes on non-resident individuals and corporations. Although an analysis of those various taxes is not presented here, each prospective unitholder should consider their potential impact on his investment in us. Although you may not be required to file a return and pay taxes in some jurisdictions if your income from that jurisdiction falls below the filing and payment requirement, you may be required to file income tax returns and to pay income taxes in other jurisdictions in which we do business or own property and may be subject to penalties for failure to comply with those requirements. In some jurisdictions, tax losses may not produce a tax benefit in the year incurred and may not be available to offset income in subsequent taxable years. Some of the jurisdictions may require us, or we may elect, to withhold a percentage of income from amounts to be distributed to a unitholder who is not a resident of the jurisdiction. Withholding, the amount of which may be greater or less than a particular unitholder’s income tax liability to the jurisdiction, generally does not relieve a nonresident unitholder from the obligation to file an income tax return. Amounts withheld will be treated as if distributed to unitholders for purposes of determining the amounts distributed by us. Please read “—Tax Consequences of Unit Ownership—Entity-Level Collections.” Based on current law and our estimate of our future operations, our general partner anticipates that any amounts required to be withheld will not be material.

Tax Consequences of Ownership of Preferred Units

A description of the material federal income tax consequences of the acquisition, ownership and disposition of preferred units will be set forth in a prospectus supplement relating to the offering of preferred units.

Tax Consequences of Ownership of Debt Securities

A description of the material federal income tax consequences of the acquisition, ownership and disposition of debt securities will be set forth in a prospectus supplement relating to the offering of debt securities.

It is the responsibility of each unitholder to investigate the legal and tax consequences, under the laws of pertinent states, localities and foreign jurisdictions, of his investment in us. Accordingly, each prospective unitholder is urged to consult his own tax counsel or other advisor with regard to those matters. Further, it is the responsibility of each unitholder to file all state, local and foreign, as well as U.S. federal tax returns, that may be required of him. Baker Botts L.L.P. has not rendered an opinion on the state, local or foreign tax consequences of an investment in us.

56

INVESTMENT IN SUMMIT MIDSTREAM PARTNERS, LP BY EMPLOYEE BENEFIT PLANS

An investment in us by an employee benefit plan is subject to additional considerations because the investments of these plans are subject to the fiduciary responsibility and prohibited transaction provisions of ERISA and the restrictions imposed by Section 4975 of the Code and provisions under any federal, state, local, non-U.S. or other laws or regulations that are similar to such provisions of the Code or ERISA (collectively, “Similar Laws”). For these purposes the term “employee benefit plan” includes, but is not limited to, qualified pension, profit-sharing and stock bonus plans, Keogh plans, simplified employee pension plans and tax deferred annuities or IRAs or annuities established or maintained by an employer or employee organization, and entities whose underlying assets are considered to include “plan assets” of such plans, accounts and arrangements (collectively, “Employee Benefit Plans”). Among other things, consideration should be given to:

The person with investment discretion with respect to the assets of an Employee Benefit Plan, often called a fiduciary, should determine whether an investment in us is authorized by the appropriate governing instrument and is a proper investment for the plan.

Section 406 of ERISA and Section 4975 of the Code prohibit Employee Benefit Plans from engaging, either directly or indirectly, in specified transactions involving “plan assets” with parties that, with respect to the Employee Benefit Plan, are “parties in interest” under ERISA or “disqualified persons” under the Code unless an exemption is available. A party in interest or disqualified person who engages in a non-exempt prohibited transaction may be subject to excise taxes and other penalties and liabilities under ERISA and the Code. In addition, the fiduciary of the ERISA plan that engaged in such a non-exempt prohibited transaction may be subject to penalties and liabilities under ERISA and the Code.

Employee Benefit Plans that are “governmental plans” (as defined in Section 3(32) of ERISA), certain “church plans” (as defined in Section 3(33) of ERISA or Section 4975(g)(3) of the Code) and non-U.S. plans (as described in Section 4(b)(4) of ERISA) are generally not subject to the requirements of ERISA or Section 4975 of the Code but may be subject to similar prohibitions under other applicable Similar Laws.

In addition to considering whether the purchase of our units is a prohibited transaction, a fiduciary should consider whether the Employee Benefit Plan will, by investing in us, be deemed to own an undivided interest in our assets, with the result that our general partner would also be a fiduciary of such Employee Benefit Plan and our operations would be subject to the regulatory restrictions of ERISA, including its prohibited transaction rules, as well as the prohibited transaction rules of the Code, ERISA and any other applicable Similar Laws.

The Department of Labor regulations and Section 3(42) of ERISA provide guidance with respect to whether, in certain circumstances, the assets of an entity in which Employee Benefit Plans acquire equity interests would be deemed “plan assets.” Under these regulations, an entity’s assets would not be considered to be “plan assets” if, among other things:

(a) the equity interests acquired by the Employee Benefit Plan are publicly offered securities—i.e., the equity interests are widely held by 100 or more investors independent of the issuer and each other, are

57

“freely transferable” (as defined in the regulations) and are registered under certain provisions of the federal securities laws;

(b) the entity is an “operating company,”—i.e., it is primarily engaged in the production or sale of a product or service, other than the investment of capital, either directly or through a majority-owned subsidiary or subsidiaries; or

(c) there is no significant investment by “benefit plan investors,” which is defined to mean that less than 25% of the value of each class of equity interest, disregarding certain interests held by our general partner, its affiliates and certain other persons, is held generally by Employee Benefit Plans.

Our assets should not be considered “plan assets” under these regulations because it is expected that the investment will satisfy the requirements in (a) and (b) above.

In light of the serious penalties imposed on persons who engage in prohibited transactions or other violations, plan fiduciaries contemplating a purchase of our units should consult with their own counsel regarding the consequences under ERISA, the Code and other Similar Laws.

58

VALIDITY OF THE SECURITIES

In connection with particular offerings of the securities offered in this prospectus in the future, and if stated in the applicable prospectus supplements, the validity of the issuance of the securities and certain other legal matters will be passed upon for us by Baker Botts L.L.P., Houston, Texas. Legal counsel to any underwriters may pass upon legal matters for such underwriters and will be named in the applicable prospectus supplement.

59

EXPERTS

The consolidated financial statements of Summit Midstream Partners, LP and subsidiaries incorporated in this prospectus by reference from the Partnership’s Current Report on Form 8-K, as filed with the SEC on November 6, 2017, and the effectiveness of the Partnership’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of Ohio Gathering Company, L.L.C. as of and for the years ended December 31, 2015 and 2014 incorporated in this prospectus by reference to Exhibit 99.3 from the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2016 have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of Ohio Condensate Company, L.L.C. as of and for the years ended December 31, 2015 and 2014 incorporated in this prospectus by reference to Exhibit 99.4 from the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2016 have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of Ohio Gathering Company, L.L.C. incorporated in this prospectus by reference to Exhibit 99.1 in the Summit Midstream Partners, LP Annual Report on Form 10-K for the year ended December 31, 2016 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

The financial statements of Ohio Condensate Company, L.L.C. incorporated in this prospectus by reference to Exhibit 99.2 in the Summit Midstream Partners, LP Annual Report on Form 10-K for the year ended December 31, 2016 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

60

Units

    % Series A Fixed-to-Floating Rate Cumulative Redeemable

Perpetual Preferred Units

(Liquidation Preference $             per unit)

PROSPECTUS    SUPPLEMENT

BofA Merrill Lynch

Credit Suisse

Morgan Stanley

Wells Fargo Securities

                    , 2017