Filed Pursuant to Rule 424(b)(5)
Registration No. 333-214259

The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to the offer and the sale of the notes has become effective under the Securities Act of 1933. This preliminary prospectus supplement is not an offer to sell the notes and it is not soliciting an offer to buy the notes in any jurisdiction where the offer or sale of the notes is not permitted.

(To prospectus dated October 26, 2016)

$125,000,000

% Convertible Senior Notes due 2023

NOTES

CONVERSION

OPTIONAL REDEMPTION AND REPURCHASE

RANKING

LISTING

Investing in the notes involves significant risks. See “Risk Factors” beginning on page S-8 of this prospectus supplement and on page 1 of the accompanying prospectus.

Neither the U.S. 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 prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We expect that the notes will be ready for delivery in book-entry-only form through The Depository Trust Company on             , 2018.

Joint Book-Running Managers

Lead Managers

Co-Managers

                    , 2018

TABLE OF CONTENTS

Prospectus Supplement

Prospectus

You should rely only on the information contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus and any free writing prospectus we authorize for use in connection with this offering. We have not, and the underwriters have not, authorized anyone to provide you with information that is different. This prospectus supplement and the accompanying prospectus are not an offer to sell or a solicitation of an offer to buy these securities in any circumstances under which the offer or sale is unlawful. We are offering to sell, and seeking offers to buy, notes only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the notes in certain jurisdictions may be restricted by law. You should

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assume that the information included, or incorporated by reference, in this prospectus supplement or the accompanying prospectus is accurate only as of the date of this prospectus supplement, the accompanying prospectus or the information we have incorporated by reference. Our financial condition, results of operations and business prospects may have changed since those dates.

We expect to deliver the notes against payment for the notes on the fourth business day following the pricing of the notes (“T+4”). Under Rule 15c6-1 of the Exchange Act (as defined below), trades in the secondary market generally are required to settle in two business days, unless the parties to a trade expressly agree otherwise. Accordingly, purchasers who wish to trade notes prior to the second business day before the settlement date will be required, by virtue of the fact that the notes initially will settle in T+4, to specify alternative settlement arrangements to prevent a failed settlement.

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FORWARD LOOKING STATEMENTS

This prospectus supplement contains various statements that contain forward-looking information regarding Helix Energy Solutions Group, Inc. and represent our expectations and beliefs concerning future events. This forward-looking information is intended to be covered by the safe harbor for “forward-looking statements” provided by the Private Securities Litigation Reform Act of 1995 as set forth in Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements included herein or incorporated herein by reference that are predictive in nature, that depend upon or refer to future events or conditions, or that use terms and phrases such as “achieve,” “anticipate,” “believe,” “estimate,” “budget,” “expect,” “forecast,” “plan,” “project,” “propose,” “strategy,” “predict,” “envision,” “hope,” “intend,” “will,” “continue,” “may,” “potential,” “should,” “could” and similar terms and phrases are forward-looking statements. Included in forward-looking statements are, among other things:

Although we believe that the expectations reflected in our forward-looking statements are reasonable and are based on reasonable assumptions, they do involve risks, uncertainties and other factors that could cause actual results to be materially different from those in the forward-looking statements. These factors include:

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Our actual results could also differ materially from those anticipated in any forward-looking statements as a result of a variety of other factors, including those discussed in “Risk Factors” and in other sections of this prospectus supplement and those discussed under “Risk Factors” in the accompanying prospectus and elsewhere in the documents that we incorporate by reference into this prospectus, including our Annual Report on Form 10-K for the year ended December 31, 2017, and in our other reports filed with the U.S. Securities and Exchange Commission (“SEC”). All forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by these risk factors. Forward-looking statements are only as of the date they are made, and other than as required under the securities laws, we assume no obligation to update or revise these forward-looking statements or provide reasons why actual results may differ.

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WHERE YOU CAN FIND ADDITIONAL INFORMATION

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 that we filed with the SEC. Certain information in the registration statement has been omitted from this prospectus supplement and the accompanying prospectus in accordance with the rules of the SEC. We are a public company and file proxy statements and annual, quarterly and special reports and other information with the SEC. Such reports and other information can be inspected and copied at the Public Reference Room of the SEC located at 100 F Street, N.E., Washington D.C. 20549. Copies of such materials can be obtained from the Public Reference Room of the SEC at prescribed rates. You can call the SEC at 1-800-SEC-0330 to obtain information on the operation of the Public Reference Room. Such materials may also be accessed electronically by means of the SEC’s home page on the Internet (www.sec.gov). Our Central Index Key, or CIK, on the SEC Website is 866829.

We make available, free of charge, through our investor relations website, our proxy statements, annual reports, quarterly reports, current reports, statements of changes in beneficial ownership of securities and amendments to those reports and statements as soon as reasonably practicable after they are filed with the SEC. The address for our website is http://www.helixesg.com and the address for the investor relations page of our website is http://phx.corporate-ir.net/phoenix.zhtml?c=94139&p=irol-irhome (neither of which is intended to be an active hyper link in this prospectus supplement). The contents of our website are not part of this prospectus supplement, and the reference to our website does not constitute incorporation by reference into this prospectus supplement of the information contained at that site.

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INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information we have filed with the SEC, which means that we can disclose important information to you without actually including the specific information in this prospectus supplement by referring you to the documents containing such information. The information incorporated by reference is an important part of this prospectus supplement and information that we file later with the SEC will automatically update and supersede this information. Any statement contained in this prospectus supplement, the accompanying prospectus or a document incorporated by reference herein will be deemed to be modified and superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement, the accompanying prospectus or a document subsequently filed with the SEC that is incorporated by reference herein modifies or supersedes the 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 or the prospectus. You should not assume that the information in this prospectus supplement is current as of any date other than the date on the front page of this prospectus supplement. Therefore, before you decide to invest in the notes, you should always check for documents we may have filed with the SEC after the filing of this prospectus supplement. We incorporate by reference into this prospectus supplement, the accompanying prospectus, 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 Exchange Act, until the offer and sale of notes under this prospectus supplement and the accompanying prospectus is complete or is otherwise terminated, in each case other than information “furnished” to the SEC and which is not deemed filed under the Exchange Act, unless we specifically provide that such “furnished” information is to be incorporated by reference in this prospectus supplement:

We will provide without charge to each person, including any beneficial owner to whom this prospectus supplement is delivered, upon written or oral request, a copy of any document incorporated by reference in this prospectus supplement, other than exhibits to any such document not specifically described above. Requests for such documents should be directed to:

Investor Relations

Helix Energy Solutions Group, Inc.

3505 West Sam Houston Parkway North

Suite 400

Houston, Texas 77043

(281) 618-0400

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RISK FACTORS

Investing in the notes involves risks. Prior to making a decision whether to invest in the notes, and in consultation with your own financial and legal advisors, you should carefully consider, among other matters, the following risk factors as well as those incorporated by reference in this prospectus supplement from our Annual Report on Form 10-K for the year ended December 31, 2017 under the headings “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and in our other filings we may make from time to time with the SEC.

Risks Related to the Notes and the Underlying Shares of Common Stock

The notes are unsecured, are effectively subordinated to all of our existing and future secured indebtedness (to the extent of the assets securing such indebtedness) and are structurally subordinated to all liabilities of our subsidiaries, including trade payables.

The notes are unsecured, are effectively subordinated to all of our existing and future secured indebtedness, to the extent of the assets securing such indebtedness and other secured obligations (to the extent of the value of the assets securing such indebtedness and other obligations, and are structurally subordinated to all liabilities of our subsidiaries, including trade payables. Our obligations under our Credit Agreement are guaranteed by all of our domestic subsidiaries (except Cal Dive I-Title XI, Inc.) and Canyon Offshore Limited, a wholly owned Scottish subsidiary, and are secured by (i) most of our assets, (ii) the shares of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.) and Canyon Offshore Limited, and (iii) most of the assets of our domestic subsidiaries (other than Cal Dive I — Title XI, Inc.) and Canyon Offshore Limited. In addition, these obligations are secured by pledges of up to 66% of the shares of certain foreign subsidiaries. See “Description of Other Indebtedness — Credit Agreement.” As of December 31, 2017, we had approximately $495.63 million of consolidated indebtedness outstanding, net of unamortized discounts and issuance costs, of which $264.21 million was secured indebtedness of Helix Energy Solutions Group, Inc. and $231.42 million of which was indebtedness of our subsidiaries.

In the event of our insolvency, bankruptcy, liquidation, reorganization, dissolution or winding up, we may not have sufficient assets to pay amounts due on any or all of the notes then outstanding. See “Description of Notes — Ranking.”

None of our subsidiaries has guaranteed or otherwise become obligated with respect to the notes. Our right to receive assets from any of our subsidiaries upon its liquidation or reorganization, and the right of holders of the notes to participate in those assets, is structurally subordinated to claims of that subsidiary’s creditors, including trade creditors. Even if we were a creditor of any of our subsidiaries, our rights as a creditor would be subordinate to any security interest in the assets of that subsidiary and any indebtedness of that subsidiary senior to that held by us. Furthermore, none of our subsidiaries is under any obligation to make payments to us, and any payments to us would depend on the earnings or financial condition of our subsidiaries and various business considerations. Statutory, contractual or other restrictions may also limit our subsidiaries’ ability to pay dividends or make distributions, loans or advances to us. For these reasons, we may not have access to any assets or cash flows of our subsidiaries to make payments on the notes.

Future issuances of shares of common stock and investor hedging activities in connection with the notes offering may depress the trading price of our common stock and the notes.

Any issuance of equity securities after this offering, including any issuance of shares of our common stock upon conversion of the notes or to our employees and directors under our long term incentive plans, will dilute the interests of our existing shareholders, including holders who have received shares of our common stock upon conversion of their notes, and could substantially decrease the trading price of our common stock and the notes. We may issue equity securities in the future for a number of reasons, including to finance our operations and business strategy (including in connection with acquisitions, strategic collaborations or other transactions), to adjust our ratio of debt to equity, to satisfy our obligations upon the exercise of outstanding warrants or options or for other reasons.

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In addition, the price of our common stock could also be affected by possible sales of our common stock by investors who view the notes as a more attractive means of equity participation in our company and by hedging or arbitrage trading activity that we expect to develop involving our common stock. The hedging or arbitrage could, in turn, affect the trading price of the notes or any common stock that holders receive upon conversion of the notes.

The share price of our common stock has been, and will likely continue to be, volatile.

The trading price of our common stock has been, and is likely to continue to be, volatile and could be subject to wide fluctuations in response to various factors, some of which are beyond our control. In addition to the factors discussed in these risk factors and elsewhere in our reports and other documents filed with the SEC, factors that may cause volatility in our share price include:

Furthermore, from time to time, the stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market and industry fluctuations, as well as general economic, political and market conditions, such as recessions, interest rate changes, international currency fluctuations or political unrest, may negatively impact the market price of our common stock. In the past, companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation, and we have been a defendant to a securities class action claim in the past. Any future securities litigation against us could result in substantial costs and divert our management’s attention.

The conversion rate of the notes may not be adjusted for all dilutive events that may occur.

As described under “Description of Notes—Adjustments to the Conversion Rate,” we will adjust the conversion rate of the notes for certain events, including, among others:

We will not adjust the conversion rate for other events, such as an issuance of our common stock for cash or in connection with an acquisition, that may adversely affect the trading price of the notes or our common stock. If we engage in any of these types of transactions, the value of the shares of common stock

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underlying your notes may be diluted. An event that adversely affects the value of the notes, but does not result in an adjustment to the conversion rate, may occur. Also, we will not increase the conversion rate to an amount that exceeds                 shares of common stock per $1,000 principal amount of notes (subject to adjustment in the same manner as the conversion rate).

Our election to pay cash in respect of some or all of our conversion obligation may have adverse consequences.

Our election to deliver cash in respect of all or a portion of our conversion obligation (other than solely cash in lieu of fractional shares) as described under “Description of Notes — Conversion Rights,” may:

We will generally deliver the consideration due upon conversion of the notes as soon as practicable, but in no event later than two business days after (1) the last trading day in the observation period (in the case of cash settlement or combination settlement) or (2) the conversion date (in the case of physical settlement). In addition, in the case of cash settlement or combination settlement, because the consideration due upon conversion is based on the trading prices of our common stock during the observation period, any decrease in the price of our common stock after you surrender your notes for conversion may significantly decrease the value of the consideration you receive upon conversion. In addition, if the trading price of our common stock at the end of such period is below the average of the volume-weighted average price of our common stock during such period, the value of any shares of common stock that you receive in satisfaction of our conversion obligation will be less than the value used to determine the number of shares of common stock you will receive.

The accounting method for convertible debt securities that may be settled in cash, such as the notes, could have a material effect on our reported financial results.

Generally accepted accounting principles in the United States (“GAAP”) require that an entity separately account for the liability and equity components of the convertible debt instruments (such as the notes) that may be settled entirely or partially in cash upon conversion in a manner that reflects the issuer’s economic interest cost. The effect on the accounting for the notes is that the equity component would be included in the common stock section of shareholders’ equity on our consolidated balance sheet and the value of the equity component would be treated as original issue discount for purposes of accounting for the debt component of the notes. As a result, we will be required to record a greater amount of non-cash interest expense in current periods presented as a result of the amortization of the discounted carrying value of the notes to their face amount over the term of the notes. We will report lower net income in our financial results because GAAP requires interest to include both the current period’s amortization of the debt discount and the instrument’s coupon interest, which could adversely affect our reported or future financial results, the trading price of our common stock and the trading price of the notes.

The increase in the conversion rate applicable to notes that holders convert in connection with a make-whole fundamental change may not adequately compensate you for the lost option value of your notes as a result of that make-whole fundamental change.

If a make-whole fundamental change occurs prior to the maturity date, we will under certain circumstances increase the conversion rate applicable to holders who convert their notes within a specified timeframe. The amount of the increase in the conversion rate depends on the date when the make-whole fundamental change becomes effective and the applicable price, as described in this prospectus

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supplement. See “Description of Notes — Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change.”

Although the increase in the conversion rate is designed to compensate you for the lost option value of your notes as a result of the make-whole fundamental change, the increase in the conversion rate is only an approximation of the lost value and may not adequately compensate you for the loss. In addition, you will not be entitled to an increased conversion rate if the applicable price is greater than $             per share of common stock or less than $             per share of common stock (in each case, subject to adjustment).

Our obligation to increase the conversion rate as described above could also be considered a penalty, in which case its enforceability would be subject to general principles of reasonableness of economic remedies. In addition, we will not increase the conversion rate to an amount that exceeds                 shares of common stock per $1,000 principal amount of notes (subject to adjustment in the same manner as the conversion rate).

Our level of indebtedness may affect our ability to satisfy our obligations under the notes.

As adjusted to include the sale of the notes we are offering hereby and giving effect to the use of proceeds described herein, the principal amount of our total consolidated long-term debt as of December 31, 2017 would have been approximately $                 million. The indenture for the notes will not restrict our ability to incur additional indebtedness.

Our level of indebtedness could have important consequences to you, because:

Our operations may not generate sufficient cash to enable us to service our debt. If we fail to make a payment on the notes, we could be in default on the notes, and this default could cause us to be in default on our other outstanding indebtedness. Conversely, a default on our other outstanding indebtedness may cause a default under the notes.

The conditional conversion feature of the notes, if triggered, may adversely affect our financial condition and operating results.

In the event the conditional conversion feature of the notes is triggered, holders of the notes will be entitled to convert the notes at any time during specified periods at their option. See “Description of Notes — Conditions for Conversion.” If one or more holders elect to convert their notes, unless we elect to satisfy our conversion obligation by delivering solely shares of our common stock (excluding cash in lieu of any fractional share), we would be required to settle a portion or all of our conversion obligation through the payment of cash, which could adversely affect our liquidity. In addition, even if holders do not elect to convert their notes, we could be required under applicable accounting rules to reclassify all or a portion of the outstanding principal amount of the notes as a current, rather than long-term, liability, which would result in a material reduction of our net working capital.

We may not have the ability to raise the funds to pay interest on the notes, to repurchase the notes upon a fundamental change, or to pay cash due upon conversion.

The notes bear interest semi-annually at a rate of         % per year. If a fundamental change occurs, holders may require us to repurchase, for cash, all or any portion of their notes at 100% of their principal

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amount plus accrued and unpaid interest. In addition, upon conversion of the notes, unless we have elected to satisfy our conversion obligation by delivering solely shares of our common stock (excluding cash in lieu of any fractional share), we will be required to pay cash in respect of all or a portion of our conversion obligation. We may not have sufficient funds to pay the interest, repurchase price or cash in respect of our conversion obligation when due. If we fail to pay interest on the notes, repurchase the notes or pay any cash payment due upon conversion when required, we will be in default under the indenture governing the notes. See “Description of Notes — Interest Payments,” “Description of Notes — Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” and “Description of Notes — Events of Default.”

The conditional conversion feature of the notes could result in your receiving less than the value of our common stock into which the notes would otherwise be convertible.

Prior to the close of business on the business day immediately preceding March 15, 2023, you may convert your notes only if specified conditions are met. If the specific conditions for conversion are not met, you will not be able to convert your notes until March 15, 2023 or thereafter.

We have made only limited covenants in the indenture for the notes, and these limited covenants may not protect your investment.

The indenture for the notes does not:

Furthermore, the indenture for the notes contains only limited protections in the event of a change of control. We could engage in many types of transactions, such as acquisitions, refinancings or recapitalizations, that could substantially affect our capital structure and the value of the notes and our common stock but may not constitute a “fundamental change” that permits holders to require us to repurchase their notes or a “make-whole fundamental change” that permits holders to convert their notes at a potentially increased conversion rate. For these reasons, you should not consider the covenants in the indenture or the repurchase features of the notes as a significant factor in evaluating whether to invest in the notes.

The occurrence of certain “make-whole fundamental changes” or any “fundamental change” will also result in redemption of some of our existing debt arrangements.

The occurrence of certain “make-whole fundamental changes” as described under “Description of Notes — Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change” or the occurrence of any “fundamental change” as described under “Description of Notes — Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” pursuant to the terms of the notes will require us to redeem our then outstanding 2032 Notes and 4.25% Convertible Senior Notes due 2022 (the “2022 Notes”).

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You may find it difficult to sell your notes.

Although the underwriters have indicated that they intend to make a market in the notes, they are not obligated to do so, and any of their market making activities may be terminated or limited at any time. In addition, although we have registered the offer and sale of the notes under the Securities Act, there can be no assurance as to the liquidity of markets for the notes, the ability of noteholders to sell their notes or the prices at which notes could be sold. The notes may trade at prices that are lower than their initial purchase price depending on many factors, including prevailing interest rates and the markets for similar securities. The liquidity of trading markets for the notes may also be adversely affected by general declines or disruptions in the markets for debt securities. Those market declines or disruptions could adversely affect the liquidity of and market for the notes independent of our financial performance or prospects. An active market for the notes may not exist or develop or, if developed, may not continue. In the absence of an active trading market, you may not be able to transfer the notes within the time or at the price you desire.

We may invest or spend the proceeds in this offering in ways with which you may not agree and in ways that may not earn a profit.

We intend to use the net proceeds from this offering to repurchase the outstanding $60.115 million principal amount of the 2032 Notes in the Repurchase Offer and to repay borrowings under our outstanding Term Loan. To the extent that any of the 2032 Notes are not purchased in the Repurchase Offer, we may use a portion of the net proceeds from this offering to repurchase or redeem the remaining 2032 Notes. However, we will retain discretion over the use of the proceeds from this offering. You may not agree with the ways we decide to use these proceeds, and our use of the proceeds may not yield any profits.

Certain provisions in the indenture for the notes and our articles of incorporation and bylaws could discourage potential acquisition proposals and could deter or prevent a change in control.

If a “fundamental change” occurs, holders of the notes will have the right, at their option, to require us to repurchase all or any portion of their notes. In the event of a “make-whole fundamental change,” we may be required to increase the conversion rate applicable to notes surrendered for conversion in connection with such make-whole fundamental change. In addition, the indenture for the notes prohibits us from engaging in certain mergers or acquisitions unless, among other things, the surviving entity assumes our obligations under the notes. Our existing convertible note indentures have similar provisions and under our Term Loan, a change of control (as defined therein) is an event of default.

Our articles of incorporation give our board of directors the authority, without any action by our shareholders, to fix the rights and preferences on up to 5,000,000 shares of undesignated preferred stock, including dividend, liquidation and voting rights. In addition, our by-laws divide our board of directors into three classes and our directors may only be removed by a supermajority vote. We are also subject to certain anti-takeover provisions of the Minnesota Business Corporation Act. We also have employment arrangements with all of our executive officers that could require cash payments in the event of a “change of control.”

Any or all of the provisions or factors described above may discourage a takeover proposal or tender offer not approved by management and our board of directors, even if our shareholders may otherwise view the proposal or tender offer as favorable.

An adverse rating of the notes may cause their trading price to fall.

We do not intend to rate the notes, but if a rating agency rates the notes, it may assign a rating that is lower than the ratings expected by investors. Ratings agencies also may lower any rating on the notes in the future. If rating agencies assign a lower-than-expected rating or reduce, or indicate that they may reduce, their ratings in the future, the trading price of the notes could significantly decline.

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Recent and future regulatory actions and other events may adversely affect the trading price and liquidity of the notes.

We expect that many investors in the notes, including potential purchasers of the notes from investors in this offering, will employ or seek to employ a convertible note arbitrage strategy. Under this strategy, investors typically short sell a certain number of shares of our common stock and adjust their short position over time while they continue to hold the notes. Investors may also implement this type of strategy by entering into swaps on our common stock in lieu of, or in addition to, short selling shares of our common stock.

The SEC and other regulatory authorities have implemented various rules and taken certain actions, and may in the future adopt additional rules and take other actions, that may impact those engaging in short selling activity involving equity securities (including our common stock). These rules and actions include Rule 201 of SEC Regulation SHO, the adoption by the Financial Industry Regulatory Authority, Inc., and the national securities exchanges of a “limit up-limit down” program, the imposition of market-wide circuit breakers that halt trading of securities for certain periods following specific market declines, and the implementation of certain regulatory reforms required by the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. Past regulatory actions, including emergency actions or regulations, have had a significant impact on the trading prices and liquidity of equity-linked instruments. Any governmental or regulatory action that similarly restricts investors’ ability to effect short sales of our common stock or enter into equity swaps on our common stock could depress the trading price of, and the liquidity of the market for, the notes.

In addition, the liquidity of the market for our common stock may decline, which could reduce the number of shares available for lending in connection with short sale transactions and the number of counterparties willing to enter into an equity swap on our common stock with a note investor. If investors and potential purchasers seeking to employ a convertible note arbitrage strategy are unable to borrow or enter into equity swaps on our common stock on commercially reasonable terms, then the trading price of, and the liquidity of the market for, the notes may significantly decline.

As a holder of notes, you will not be entitled to any rights with respect to our common stock, but you will be subject to all changes made with respect to our common stock.

If you hold notes, you will not, as such, be entitled to any rights with respect to our common stock (including, without limitation, voting rights and rights to receive any dividends or other distributions on our common stock), but you will be subject to all changes affecting our common stock. You will have the rights with respect to our common stock only if you convert your notes and become a record owner of common stock on the conversion date (in the case of physical settlement) or the last trading day of the applicable observation period (in the case of combination settlement), and only to the extent that we are obligated to deliver to you shares of common stock in respect of our conversion obligation. For example, in the event that an amendment is proposed to our articles of incorporation or bylaws requiring shareholder approval and the record date for determining the shareholders of record entitled to vote on the amendment occurs prior to the date you are deemed the record owner of our common stock, if any, due upon conversion, you will not be entitled to vote on the amendment, although you will nevertheless be subject to any changes in the powers, preferences or special rights of our common stock. In addition, because the notes may be settled by delivery of solely cash, you may not receive any shares upon conversion.

We have never declared or paid cash dividends on our common stock, and we do not intend to pay cash dividends in the foreseeable future.

We currently intend to retain our earnings, if any, for the future operation and growth of our business. As a result, we do not anticipate paying cash dividends on our common stock in the foreseeable future. Because we do not anticipate paying cash dividends for the foreseeable future, holders who convert their notes and receive shares of our common stock will not realize a return on their investment unless the trading price of our common stock appreciates, which we cannot assure.

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You may have to pay U.S. federal income tax if we make or fail to make certain adjustments to the conversion rate of the notes in certain circumstances, even if you do not receive any corresponding cash distribution.

The conversion rate of the notes will be adjusted in certain circumstances, as described under “Description of Notes — Adjustments to the Conversion Rate.” Adjustments (or failures to make adjustments) that are considered to have the effect of increasing the proportionate interest of a holder of a note in our assets or earnings and profits may in some circumstances result in a deemed distribution to the holder for U.S. federal income tax purposes, even though the holder has not received any cash or property as a result of such adjustments. Adjustments to the conversion rate made pursuant to a bona fide reasonable adjustment formula that have the effect of preventing the dilution of the interest of the holders of the notes, however, will generally not be considered to result in a deemed distribution. Certain of the possible conversion rate adjustments provided in the notes (including, without limitation, adjustments in respect of taxable dividends to holders of our common stock and adjustments to the conversion rate upon a make-whole fundamental change) may not qualify as being pursuant to a bona fide reasonable adjustment formula. If such an adjustment is made and does not so qualify, a holder generally will be deemed to have received a distribution even if the holder does not receive any cash or property as a result of such adjustment. Any deemed distributions will be taxed in the same manner as an actual distribution, but may not be eligible for the reduced rates of tax applicable to the receipt of dividend income by certain non-corporate holders or the dividends-received deduction. With respect to a non-U.S. holder (as defined below in “Material U.S. Federal Income Tax Considerations”), such deemed distribution, to the extent treated as a dividend, generally will be subject to U.S. federal withholding tax (currently at a 30% rate, or such lower rate as may be specified by an applicable treaty as to which a non-U.S. holder has appropriately claimed the benefit). Such withholding tax (or any applicable backup withholding with respect to a deemed distribution) may be withheld from payments of interest and payments of cash or common stock upon conversion, repurchase or maturity of the notes or sales proceeds received by a holder, or if any withholding taxes (including backup withholding) are paid on behalf of a holder, those amounts may be set off against such payments of cash or common stock received by, or other funds or assets of, such holder. See “Material U.S. Federal Income Tax Considerations.”

Conversion of notes into cash or a combination of both cash and our common stock will require certain holders to recognize taxable gains for U.S. federal income tax purposes.

Upon the conversion of a note into cash or a combination of both cash and our common stock, certain holders will generally be required to recognize gain on the conversion for U.S. federal income tax purposes. Prospective investors should carefully review the information regarding tax considerations relevant to an investment in the notes set forth under “Material U.S. Federal Income Tax Considerations” and are also urged to consult their own tax advisors prior to investing in the notes.

You may be subject to tax upon a change in conversion consideration or subsequent conversion even though you do not receive a corresponding cash distribution.

In certain circumstances, the conversion consideration may be changed, and depending on the circumstances at the time of such an event, such a change may result in a taxable event for U.S. federal income tax purposes. In addition, a subsequent conversion for the new conversion consideration may be a taxable event regardless of the chosen settlement method. See “Material U.S. Federal Income Tax Considerations.”

Because the notes will initially be held in book-entry form, noteholders must rely on DTC’s procedures to exercise their rights and remedies.

We will initially issue the notes in the form of one or more “global notes” registered in the name of Cede & Co., as nominee of DTC. Beneficial interests in global notes will be shown on, and transfers of global notes will be effected only through, the records maintained by DTC. Except in limited

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circumstances, we will not issue certificated notes. See “Description of Notes — Book-Entry Delivery and Form.” Accordingly, if you own a beneficial interest in a global note, then you will not be considered an owner or holder of the notes. Instead, DTC or its nominee will be the sole holder of the notes. Payments of principal, interest and other amounts on global notes will be made to the paying agent, who will remit the payments to DTC. We expect that DTC will then credit those payments to the DTC participant accounts that hold book-entry interests in the global notes and that those participants will credit the payments to indirect DTC participants. Unlike persons who have certificated notes registered in their names, owners of beneficial interests in global notes will not have the direct right to act on our solicitations for consents or requests for waivers or other actions from noteholders. Instead, those beneficial owners will be permitted to act only to the extent that they have received appropriate proxies to do so from DTC or, if applicable, a DTC participant. The applicable procedures for the granting of these proxies may not be sufficient to enable owners of beneficial interests in global notes to vote on any requested actions on a timely basis.

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USE OF PROCEEDS

We estimate that our net proceeds from the sale of the notes will be approximately $                 million after deducting the underwriting fees and all estimated offering expenses that are payable by us. We intend to use the net proceeds from the sale of the notes to repurchase the outstanding $60.115 million principal amount of the 2032 Notes in the Repurchase Offer and to repay borrowings under our outstanding Term Loan. To the extent that any of the 2032 Notes are not purchased in the Repurchase Offer, we may use a portion of the net proceeds from this offering to repurchase or redeem the remaining 2032 Notes.

As of March 9, 2018, we had outstanding $60.115 million principal amount of 2032 Notes, and the 2032 Notes mature on March 15, 2032. Interest on the 2032 Notes accrues at a rate of 3.25% per year. For a description of our offer to repurchase the outstanding 2032 Notes in the Repurchase Offer, see “Summary — Recent Developments.”

As of March 9, 2018, we had $97.500 million of borrowings outstanding under our Term Loan, which bore interest of a weighted average interest rate of 5.90%. The Term Loan matures on June 30, 2020. Borrowings under the Term Loan currently bear interest at the LIBOR rate plus 4.25%. Within the past year, we have used borrowings under our Term Loan to repay a portion of the indebtedness under our then-outstanding term loan. Because affiliates of Wells Fargo Securities, LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated, ING Financial Markets LLC and Regions Securities LLC are lenders under our Term Loan and each will receive 5% or more of the net proceeds from this offering due to the repayment of borrowings under our Term Loan, each of these underwriters is deemed to have a conflict of interest within the meaning of the FINRA Rule 5121. Accordingly, this offering is being conducted in accordance with FINRA Rule 5121, which requires, among other things, that a “qualified independent underwriter” participate in the preparation of, and exercise the usual standards of “due diligence” with respect to, the registration statement and this prospectus. Raymond James & Associates, Inc. has agreed to act as a qualified independent underwriter for this offering. For more information, see “Underwriting (Conflicts of Interest).”

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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 basis:

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PRICE RANGE OF COMMON STOCK

Our common stock trades on the NYSE under the symbol “HLX.” The following table sets forth, for the periods indicated, the high and low reported intraday sale prices of our common stock as reported on the NYSE:

On March 12, 2018, the last reported closing sale price of our common stock on the NYSE was $6.52 per share.

DIVIDEND POLICY

We have never declared or paid cash dividends on our common stock and do not intend to pay cash dividends in the foreseeable future. We currently intend to retain earnings, if any, for the future operation and growth of our business. In addition, our financing arrangements prohibit the payment of cash dividends on our common stock.

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CAPITALIZATION

The following table shows:

You should read this table in conjunction with, and this table is qualified in its entirety by reference to, the information contained in “Use of Proceeds” on page S-17 of this prospectus supplement, as well as our consolidated financial statements and the related notes included in our Annual Report on Form 10-K for the year ended December 31, 2017 filed with the SEC on February 23, 2018 and our other reports filed with the SEC that are incorporated by reference herein.

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DESCRIPTION OF NOTES

We will issue the notes pursuant to an indenture dated as of November 1, 2016 (the “Base Indenture”) between us and The Bank of New York Mellon Trust Company, N.A., as trustee (the “trustee”), as amended and supplemented by a second supplemental indenture, to be entered into on or about the date the notes are first issued (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), between us and the trustee. The terms of the notes include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”).

The following summary of the terms of the notes and the Indenture does not purport to be complete and is subject, and qualified in its entirety by reference, to the detailed provisions of the notes and the Indenture. You should read carefully the section entitled “Description of Our Debt Securities” in the accompanying prospectus for a description of other material terms of the notes and the Indenture.

You may request a copy of the Indenture (when executed) from us as described under “Where You Can Find More Information.”

For purposes of this summary, the terms “Helix,” “Company,” “we,” “us” and “our” refer only to Helix Energy Solutions Group, Inc. and not to any of its subsidiaries, unless we specify otherwise.

General

We are offering $125.0 million aggregate principal amount of our convertible senior notes due 2023 (the “notes”). The notes bear interest at a rate of     % per annum payable semi-annually in arrears on March 15 and September 15 of each year, beginning on September 15, 2018, to holders of record at the close of business on the preceding March 1 and September 1, respectively, except as described below.

The notes we are offering:

The notes mature on September 15, 2023, unless earlier converted, redeemed or repurchased.

All cash payments on the notes will be made in U.S. dollars.

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We will issue the notes in denominations of integral multiples of $1,000 principal amount, without coupons. We will initially issue the notes as global securities in book-entry form. We will make payments in respect of notes represented by global securities by wire transfer of immediately available funds to DTC or its nominee as registered owner of the global securities. We will make payments in respect of notes that are issued in certificated form by wire transfer of immediately available funds to the accounts specified by each holder of more than $5.0 million aggregate principal amount of the notes. However, if a holder of a certificated note does not specify an account, or holds $5.0 million or less in aggregate principal amount of the notes, then we will mail a check to that holder’s registered address.

We may, from time to time, without notice to or the consent of the holders, reopen the Indenture under which the notes will be issued and issue additional notes in an unlimited aggregate principal amount with the same terms (subject to certain exceptions) as the notes offered hereby, in an unlimited aggregate principal amount, provided if the additional notes are not fungible with the notes offered hereby for United States federal income tax purposes, then they must be issued with a different CUSIP number. The notes offered hereby and any additional notes would be treated as a single class for all purposes under the Indenture and would vote together as one class on all matters with respect to the notes.

You may convert certificated notes at the office of the conversion agent, present certificated notes for registration of transfer at the office of the registrar for the notes and present certificated notes for payment at maturity at the office of the paying agent. We have appointed the trustee as the initial conversion agent, registrar and paying agent for the notes. We will not provide a sinking fund for the notes. The Indenture does not contain any financial covenants and will not limit our ability to incur additional indebtedness, including senior or secured indebtedness, pay dividends or issue or repurchase our securities. In addition, the Indenture does not provide any protection to holders of notes in the event of a highly leveraged transaction or a change in control, except as, and only to the limited extent, described under “— Conversion Rights — Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change,” “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” and “— Consolidation, Merger and Sale of Assets.”

If any interest payment date, maturity date, redemption date, repurchase date or settlement date (including upon the occurrence of a fundamental change, as described below) falls on a day that is not a business day, then the required payment will be made on the next succeeding business day with the same force and effect as if made on the date that the payment was due, and no additional interest will accrue on that payment for the period from and after the interest payment date, maturity date, redemption date or repurchase date (including upon the occurrence of a fundamental change, as described below), as the case may be, to that next succeeding business day. Solely for purposes of the immediately preceding sentence, a day on which the applicable place of payment is authorized or required by law or executive order to close or be closed will be deemed not to be a “business day.”

Ranking

The notes will be our general unsecured senior obligations and will rank equally in right of payment with all our other unsecured senior indebtedness. However, the notes will be effectively subordinated to any of our existing and future secured indebtedness and other obligations to the extent of the value of the assets securing the indebtedness or other obligations. Our obligations under our credit agreement are guaranteed by our domestic subsidiaries (except Cal Dive I-Title XI, Inc.), and Canyon Offshore Limited, a wholly owned Scottish subsidiary, and are secured by (i) most of our assets, (ii) the shares of our domestic subsidiaries (other than Cal Dive I-Title XI, Inc.) and Canyon Offshore Limited and (iii) most of the assets of our domestic subsidiaries (other than Cal Dive I-Title XI, Inc.) and Canyon Offshore Limited. In addition, we have pledged up to 66% of the shares of certain foreign subsidiaries to the lenders as additional security. See “Description of Other Indebtedness — Credit Agreement.” The notes will also be effectively subordinated to all liabilities, including trade payables and lease obligations, of our subsidiaries. Any right

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by us to receive the assets of any of our subsidiaries upon a liquidation or reorganization of that subsidiary, and the consequent right of the holders of the notes to participate in those assets, will be effectively subordinated to the claims of that subsidiary’s creditors, except to the extent that we are recognized as a creditor of such subsidiary, in which case our claims would still be effectively subordinated to any security interests in the assets of such subsidiary and subordinated to any indebtedness of such subsidiary that is senior to that held by us.

As of December 31, 2017, we had approximately $495.63 million of consolidated indebtedness outstanding, of which $264.21 million was secured indebtedness of Helix Energy Solutions Group, Inc. and $231.42 million of which was indebtedness of our subsidiaries.

Our subsidiaries are separate and distinct legal entities and have no obligation, contingent or otherwise, to pay any amounts due on the notes or to make any funds available for payment on the notes, whether by dividends, loans or other payments. In addition, the payment of dividends and the making of loans and advances or other payments to us by our subsidiaries may be subject to statutory, regulatory, contractual or other restrictions, will depend on their earnings or financial condition and are subject to various business considerations. As a result, we may be unable to gain access to the cash flow or assets of our subsidiaries.

The Indenture does not limit the amount of additional indebtedness, including senior or secured indebtedness, which we can create, incur, assume or guarantee, nor does the Indenture limit the amount of indebtedness or other liabilities that our subsidiaries can create, incur, assume or guarantee.

Interest Payments

We will pay interest on the notes at a rate of     % per annum, payable semi-annually in arrears on each March 15 and September 15 of each year, beginning on September 15, 2018. Except as described below, we will pay interest that is due on an interest payment date to holders of record at the close of business on the preceding March 1 and September 1 (each, a “record date”), respectively. Interest will accrue on the notes from, and including,                 , 2018 or from, and including, the last date in respect of which interest has been paid or provided for, as the case may be, to, but excluding, the next interest payment date or maturity date, as the case may be. We will pay interest on the notes on the basis of a 360-day year consisting of twelve 30-day months.

If notes are converted after the close of business on a record date but prior to the open of business on the next interest payment date, holders of such notes at the close of business on such record date will, on such interest payment date, receive the full amount of the accrued and unpaid interest payable on such notes on such interest payment date notwithstanding the conversion. However, a holder who surrenders a note for conversion after the close of business on a record date but prior to the open of business on the next interest payment date (whether or not the holder of record as of the close of business on such record date) must pay to the conversion agent, upon surrender, an amount equal to the full amount of accrued and unpaid interest payable on the corresponding interest payment date on the note so converted; provided that no such interest payment need be made to us:

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Conversion Rights

If the conditions for conversion of the notes described under “— Conditions for Conversion” and “— Conversion Procedures” are satisfied, holders of notes may, subject to prior maturity or repurchase, convert their notes in integral multiples of $1,000 principal amount based on an initial conversion rate of                  shares of common stock per $1,000 principal amount of notes (which represents an initial conversion price of approximately $        per share of common stock). The conversion rate, and thus the conversion price, will be subject to adjustment as described below. Except as described below, we will not make any payment or other adjustment on conversion with respect to any accrued interest, if any, on the notes, and we will not adjust the conversion rate to account for accrued and unpaid interest, if any. Instead, accrued interest, if any, will be deemed to be paid by the consideration received by the holder upon conversion. As a result, accrued interest, if any, is deemed to be paid in full rather than cancelled, extinguished or forfeited. Upon conversion of the notes into a combination of cash and shares of our common stock, accrued and unpaid interest, if any, will be deemed to be paid first out of the cash paid upon such conversion.

We will not issue fractional shares upon conversion of notes. Instead, we will pay cash in lieu of fractional shares based on the closing sale price (as defined below) of our common stock on the conversion date (in the case of physical settlement) or the volume-weighted average price per share of our common stock on the last trading day of the relevant observation period (as defined below) (in the case of combination settlement).

In certain circumstances, a holder must, upon conversion, pay interest if the conversion occurs after the close of business on a record date and prior to the open of business on the next interest payment date. See “— Interest Payments” above. A note for which a holder has delivered a fundamental change repurchase notice, as described below, requiring us to repurchase the note may be surrendered for conversion only if the holder withdraws the notice in accordance with the Indenture.

If we call a holder’s notes for redemption, the holder may convert the notes only until the close of business on the second business day prior to the redemption date unless we fail to pay the redemption price.

“Closing sale price” on any date means, as determined by us, the per share price of the referenced security on such date, determined (i) on the basis of the closing per share sale price (or if no closing per share sale price is reported, the average of the bid and ask prices per share or, if more than one in either case, the average of the average bid prices per share and the average ask prices per share) on such date on the principal U.S. national or regional securities exchange on which shares of the referenced security are listed; or (ii) if shares of the referenced security are not listed on a U.S. national or regional securities exchange, as reported by OTC Markets Group Inc. or a similar organization; provided, however, that in the absence of any such report or quotation, the closing sale price shall be the price determined by a nationally recognized independent investment banking firm retained by us for such purpose as most accurately reflecting the per share price that a fully informed buyer, acting on his own accord, would pay to a fully informed seller, acting on his own accord, in an arms-length transaction, for a share of the referenced security.

We may appoint any bid solicitation agent, and we may change such bid solicitation agent.

“Trading day” means, with respect to the referenced security, a day during which (i) trading in the referenced security generally occurs on the principal U.S. national or regional securities exchange on which the referenced security is then listed or, if the referenced security is not then listed on a U.S. national or regional securities exchange, on the principal other market on which the referenced security is then traded,

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and (ii) a “market disruption event” (as defined below) has not occurred; provided, however, that if the referenced security is not listed for trading or quotation on or by any exchange, bureau or other organization, “trading day” will mean any business day.

“Market disruption event” means, with respect to a referenced security on any date such reference security is listed for trading or quotation on or by any exchange, bureau or other organization, the occurrence or existence, during the one-half hour period ending at the scheduled close of trading on such date on the principal U.S. national or regional securities exchange or other market on which such referenced security is listed for trading or trades, of any material suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant exchange or otherwise) in such referenced security or in any options, contracts or futures contracts relating to such referenced security.

Conditions for Conversion

The notes will be convertible only during certain periods or in certain circumstances, which we describe below. If the notes become convertible, we will provide written notice to the trustee, the conversion agent and each holder, and we will publicly announce, through a reputable national newswire service, that the notes have become convertible, stating, among other things:

We will send the notice as soon as practicable, but in no event later than the open of business on the business day following the date the notes become convertible as a result of the event. Holders may surrender their notes for conversion only in the following circumstances:

Conversion Based on Price of Shares of Common Stock

Prior to March 15, 2023, holders may surrender their notes for conversion during any calendar quarter after the calendar quarter ending June 30, 2018 (and only during such calendar quarter), if the closing sale price of our common stock for each of 20 or more trading days (whether or not consecutive) in a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 130% of the conversion price of the notes (the “conversion trigger price”) in effect on each applicable trading day.

Our board of directors (or a committee thereof) will make appropriate adjustments to the closing sale price of our common stock, in its good faith determination, to account for any adjustment to the conversion rate that becomes effective, or any event requiring an adjustment to the conversion rate where the “ex-dividend date” of the event occurs, during the 30 consecutive trading day period described above.

Conversion upon Satisfaction of the Trading Price Condition

Prior to March 15, 2023, holders may surrender their notes for conversion during the five consecutive business days immediately after any five consecutive trading day period (we refer to this five consecutive trading day period as the “note measurement period”) in which the trading price per $1,000 principal amount of the notes, as determined following a request by a holder of notes in accordance with the procedures described below, for each trading day in that note measurement period was equal to or less than 97% of the conversion value of the notes on such trading day. We refer to this condition as the “trading price condition.”

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Solely for purposes of the trading price condition, the “conversion value” per $1,000 principal amount of notes on each trading day in the note measurement period is the product of the closing sale price of our common stock and the conversion rate of the notes in effect on that trading day.

The bid solicitation agent will have no obligation to determine the trading price of the notes unless we have requested it to do so, and we will have no obligation to make such request unless a holder of at least $1.0 million aggregate principal amount of notes provides us with written notice that includes reasonable evidence that the trading price per $1,000 principal amount of the notes would be equal to or less than 97% of the conversion value of the notes. At such time, we will instruct the bid solicitation agent to determine the trading price of the notes for each of the next five trading days and on each succeeding trading day until the trading price condition is no longer satisfied.

The “trading price” of the notes on any date of determination (the “determination date”) means the average of the secondary market bid quotations obtained by the bid solicitation agent for $2.0 million aggregate principal amount of the notes at approximately 3:30 p.m., New York City time, on such determination date from three independent nationally recognized securities dealers we select; provided, however, that if:

provided, further, that if no bids are received for such determination date, then the trading price of the notes on any date of determination will be deemed to be less than 97% of the conversion value of the notes on such determination date.

Conversion upon Notice of Redemption

If we call any or all of the notes for redemption, a holder may convert any of its notes at any time prior to the close of business on the second business day immediately prior to the redemption date, unless we fail to pay the redemption price.

Conversion upon the Occurrence of Certain Corporate Transactions

If, prior to March 15, 2023, there occurs (1) a “fundamental change” (as described under “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change”); a (2) “make-whole fundamental change” (as described under “— Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change”) or (3) a “common stock change event” (as described under “— Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales,” other than, in the case of this clause (3), a transaction described in clause (1) under such caption that complies with our obligations described below under the caption “— Consolidation, Merger and Sale of Assets,” if applicable, and is not a fundamental change or make-whole fundamental change), in each case other than a merger or other business combination transaction that is effected solely to change our jurisdiction of incorporation and that does not constitute a fundamental change or a make-whole fundamental change, then a holder may surrender its notes for conversion at any time during the period that begins on, and includes, the effective date of the transaction and ends on, and includes, the 35th business day after the effective date of the transaction (or, if such transaction also constitutes a fundamental change, until the related fundamental change repurchase date). We will notify holders and the trustee of any such transaction no later than the actual effective date of such transaction. In addition, if the transaction is a “fundamental change,” then the notes may also be surrendered for repurchase as described below under “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change.” Holders that convert their notes in connection with a “make-whole fundamental change” may in some circumstances also be

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entitled to an increased conversion rate. See “— Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change.”

In addition, if we elect to:

then we must notify holders of the action or event at least 45 business days before the ex-dividend date for such distribution. Once we have given such notice, holders may surrender their notes for conversion at any time until the earlier of 5:00 p.m., New York City time, on the business day immediately preceding the ex-dividend date for such distribution and our announcement that such distribution will not take place, even if the notes are not otherwise convertible at such time. However, we will not be required to provide such notice, and holders will not have the right to convert their notes pursuant to the provision described in the preceding sentence on account of a distribution, if each holder participates, at the same time and upon the same terms as holders of our common stock and solely as a result of holding the notes, in such distribution without having to convert their notes as if such holder held a number of shares of common stock equal to the conversion rate in effect on the record date for such distribution multiplied by the principal amount (expressed in thousands) of notes held by such holder.

Conversion on or after March 15, 2023

The notes may be surrendered for conversion at any time from, and including, March 15, 2023 to, and including, the business day immediately preceding September 15, 2023, regardless of the foregoing conditions.

Conversion Procedures

To convert its note into shares of our common stock, cash or a combination of cash and shares of our common stock, as the case may be, a holder of a certificated note must:

If a holder holds a beneficial interest in a global note, to convert such note, a holder must comply with the last two requirements listed above and comply with DTC’s procedures for converting a beneficial interest in a global note. The date a holder complies with these requirements is the “conversion date” under the Indenture. A holder receiving shares of our common stock upon conversion will not be entitled to any

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rights as a holder of our common stock, including, among other things, the right to vote, respond to tender offers and receive dividends and notices of shareholder meetings, until the close of business on the conversion date (in the case of physical settlement) or the close of business on the last VWAP trading day of the applicable observation period (in the case of combination settlement).

Settlement Elections

Upon conversion of the notes, in satisfaction of our conversion obligation, we will pay or deliver, as the case may be, to holders, at our election, (i) shares of our common stock, together with cash in lieu of any fractional share (which we refer to as “physical settlement”); (ii) cash (which we refer to as “cash settlement”); or (iii) a combination of cash and shares of our common stock, together with cash in lieu of any fractional share (which we refer to as “combination settlement”). As used in this prospectus supplement, “settlement method” means physical settlement, cash settlement or combination settlement, as applicable.

We will inform the holders through the trustee of the settlement method we choose to satisfy our obligation upon conversion (and the specified cash amount (as defined below), if applicable), as follows:

provided, however, that if we call any notes for redemption, then (i) we will specify in the related redemption notice the settlement method that will apply to all conversions with a conversion date that occurs on or after the date we send such redemption notice and before the related redemption date; and (ii) if the related redemption date is on or after the 45th scheduled trading day immediately preceding the maturity date, then such settlement method must be the same settlement method that applies to all conversions with a conversion date that occurs on or after the 45th scheduled trading day immediately preceding the maturity date. Except as provided in the preceding sentence, we must use the same settlement method for all conversions with a conversion date that occurs on the same day, but we will not be obligated to use the same settlement method for conversions with conversion dates that occur on different days.

If we fail to give any notice within the time periods described as to how we intend to settle, then we will be deemed to have elected the “default settlement method” (as defined below) to apply and such failure will not be deemed to be a default under the Indenture. If we elect “combination settlement” to apply but we fail to specify the specified cash amount, then the specified cash amount will be deemed to be $1,000 per $1,000 principal amount of notes.

The “default settlement method” means physical settlement (as defined below). We may, from time to time, change the default settlement method, to any settlement method that we are then permitted to elect, by sending notice of the new default settlement method to the holders of the notes.

Upon surrender of your notes for conversion, we will deliver cash, shares of our common stock or a combination thereof as described below under “— Settlement Upon Conversion.”

Settlement Upon Conversion

Except as described below under the captions “— Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change — The Increase in the Conversion Rate,” “— Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales” and “— Adjustments to the Conversion Rate,” we will pay or deliver, as applicable, the consideration due upon

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conversion as follows: (i) if cash settlement or combination settlement applies, on or before the second business day immediately after the last VWAP trading day of such observation period; and (ii) if physical settlement applies, on or before the second business day immediately after such conversion date.

“Relevant exchange” means the NYSE or, if our common stock is not then listed on the NYSE, the principal U.S. national or regional securities exchange on which our common stock is listed for trading.

The amount of cash and number of shares of our common stock, as the case may be, due upon conversion will be as follows:

The “daily settlement amount” per $1,000 principal amount of notes to be converted will consist of the following for each of the 40 consecutive VWAP trading days in the relevant observation period:

“Specified cash amount” means, with respect to the conversion of a note to which combination settlement applies, the maximum cash amount per $1,000 principal amount of such note deliverable upon such conversion (excluding cash in lieu of any fractional share of common stock).

The “daily conversion value” means, for each of the 40 consecutive VWAP trading days in the observation period, one-40th of the product of (i) the conversion rate in effect on such VWAP trading day and (ii) the volume-weighted average price of our common stock on such VWAP trading day.

The “volume-weighted average price” of our common stock on any VWAP trading day means such price per share of our common stock as displayed on Bloomberg (or any successor service) page “HLX <equity> AQR” in respect of the period from the scheduled open of trading until the scheduled close of trading of the primary trading session on such VWAP trading day; or, if such price is not available, the volume-weighted average price means the market value per share of our common stock on such day as determined, using a volume-weighted average price method, by a nationally recognized independent investment banking firm retained for this purpose by us.

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The “observation period” means:

“VWAP trading day” means a day on which (i) there is no VWAP market disruption event; and (ii) trading in our common stock generally occurs on the principal U.S. national or regional securities exchange on which our common stock is then listed or, if our common stock is not then listed on a U.S. national or regional securities exchange, on the principal other market on which our common stock is then traded. If our common stock is not so listed or traded, then “VWAP trading day” means a business day.

“VWAP market disruption event” means, with respect to any date, (i) the failure by the principal U.S. national or regional securities exchange on which our common stock is then listed, or, if our common stock is not then listed on a U.S. national or regional securities exchange, the principal other market on which our common stock is then traded, to open for trading during its regular trading session on such date; or (ii) the occurrence or existence, for more than one half hour period in the aggregate, of any suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant exchange or otherwise) in our common stock or in any options, contracts or futures contracts relating to our common stock, and such suspension or limitation occurs or exists at any time before 1:00 p.m., New York City time, on such date.

“Scheduled trading day” means a day that is scheduled to be a trading day on the primary United States national securities exchange or market on which our common stock is listed or admitted for trading. If our common stock is not so listed or admitted for trading, “scheduled trading day” means any business day.

Adjustments to the Conversion Rate

The applicable conversion rate will be subject to adjustment, without duplication, upon the occurrence of any of the following events, except that we will not make any adjustment to the conversion rate if each holder of notes participates (other than in the case of a transaction described in clauses (1) or (5) below), at the same time and upon the same terms as holders of our common stock and solely as a result of holding the notes, in any of the transactions described below without having to convert such holder’s notes as if such holder held a number of shares of common stock equal to the conversion rate, multiplied by the principal amount (expressed in thousands) of notes held by such holder:

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where,

Any adjustment made under this clause (1) shall become effective immediately after the open of business on the ex-dividend date for such dividend or distribution, or immediately after the open of business on the effective date for such share split or share combination, as the case may be. If any dividend or distribution of the type described in this clause (1) is declared but not so paid or made, or any share split or combination of the type described in this clause (1) is announced but the outstanding shares of our common stock are not split or combined, as the case may be, the conversion rate shall be immediately readjusted, effective as of the date our board of directors (or a committee thereof) determines not to pay such dividend or distribution, or not to split or combine the outstanding shares of our common stock, as the case may be, to the conversion rate that would then be in effect if such dividend, distribution, share split or share combination had not been declared or announced.

where,

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Any increase made under this clause (2) will be made successively whenever any such rights, options or warrants are distributed and shall become effective immediately after the open of business on the ex-dividend date for such distribution. To the extent that shares of common stock are not delivered after the expiration of such rights, options or warrants, the conversion rate shall be decreased to the conversion rate that would then be in effect had the increase with respect to the distribution of such rights, options or warrants been made on the basis of delivery of only the number of shares of common stock actually delivered. If such rights, options or warrants are not so distributed, the conversion rate shall be decreased to be the conversion rate that would then be in effect if such ex-dividend date for such distribution had not occurred.

For purposes of this clause (2) and the provisions described above under the caption “— Conditions for Conversion — Conversion upon the Occurrence of Certain Corporate Transactions,” in determining whether any rights, options or warrants entitle the holders thereof to subscribe for or purchase shares of our common stock at less than such average of the closing sale prices for the 10 consecutive trading-day period ending on, and including, the trading day immediately preceding the date such distribution is announced, and in determining the aggregate offering price of such shares of our common stock, there shall be taken into account any consideration received by us for such rights, options or warrants and any amount payable on exercise or conversion thereof, with the value of such consideration, if other than cash, to be determined by our board of directors (or a committee thereof).

then the conversion rate will be increased based on the following formula:

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where,

If “FMV” (as defined above) is equal to or greater than the “SP” (as defined above), then, in lieu of the foregoing increase, each holder of a note shall receive, for each $1,000 principal amount of notes it holds, at the same time and upon the same terms as holders of our common stock, the amount and kind of our capital stock, evidences of our indebtedness, other assets, securities, property, rights, options or warrants that such holder would have received as if such holder owned a number of shares of common stock equal to the conversion rate in effect on the record date for the distribution.

Any increase made under this clause (3)(a) will become effective immediately after the open of business on the ex-dividend date for such distribution. If such distribution is not so paid or made, the conversion rate shall be decreased to be the conversion rate that would then be in effect if such distribution had not been declared.

where,

The adjustment to the conversion rate under the preceding paragraph will be determined as of the end of the spin-off valuation period but will be given effect immediately after the open of business

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on the ex-dividend date for the spin-off, with retroactive effect. If a note is converted and the conversion date (in the case of physical settlement) or any VWAP trading day of the applicable observation period (in the case of cash settlement or combination settlement) occurs during the spin-off valuation period, then, notwithstanding anything to the contrary, we will, if necessary, delay the settlement of such conversion until the second business day after the last day of the spin-off valuation period.

where,

If “C” (as defined above) is equal to or greater than “SP” (as defined above), then, in lieu of the foregoing increase, each holder of a note shall receive, for each $1,000 principal amount of notes, at the same time and upon the same terms as holders of our common stock, the amount of cash that such holder would have received as if such holder owned a number of shares of our common stock equal to the conversion rate on the record date for such cash dividend or distribution. Such increase shall become effective immediately after the open of business on the ex-dividend date for such dividend or distribution. If such dividend or distribution is not so paid, the conversion rate shall be decreased, effective as of the date our board of directors (or a committee thereof) determines not to make or pay such dividend or distribution, to be the conversion rate that would then be in effect if such dividend or distribution had not been declared.

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where,

The adjustment to the conversion rate pursuant to this clause (5) will be determined as of the end of the tender/exchange offer valuation period but will be given effect immediately after the expiration time, with retroactive effect. If a note is converted and the conversion date (in the case of physical settlement) or any VWAP trading day of the applicable observation period (in the case of cash settlement or combination settlement) occurs during the tender/exchange offer valuation period, then, notwithstanding anything to the contrary, we will, if necessary, delay the settlement of such conversion until the second business day after the last day of the tender/exchange offer valuation period.

Notwithstanding anything to the contrary, if:

then, solely for purposes of such conversion, we will, without duplication, give effect to such adjustment on such conversion date (in the case of physical settlement) or such VWAP trading day (in the case of combination settlement). In such case, if the date we are otherwise required to deliver the consideration due upon such conversion is before the first date on which the amount of such adjustment can be determined, then we will (i) deliver, on such date we are otherwise required by the indenture, the consideration due upon such conversion based on the applicable unadjusted conversion rate(s); and (ii) deliver, on the business day immediately after such first date, any additional consideration arising from giving effect to such adjustment to the applicable conversion rate(s).

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Notwithstanding anything to the contrary in the indenture or the notes, if:

then (x) such conversion rate adjustment will not be given effect for such conversion (in the case of physical settlement) or for such VWAP trading day (in the case of combination settlement); and (y) the shares of common stock, if any, issuable upon such conversion (in the case of physical settlement) or issuable with respect to such VWAP trading day (in the case of combination settlement) based on such unadjusted conversion rate will be entitled to participate in such dividend or distribution.

The “ex-dividend date” is the first date on which our common stock trades on the applicable exchange or in the applicable market, regular way, without the right to receive the issuance, dividend or distribution in question from us or, if applicable, from the seller of our common stock on such exchange or market (in the form of due bills or otherwise) as determined by such exchange or market.

As used in this section titled “— Adjustments to the Conversion Rate,” “record date” means, with respect to any dividend, distribution or other transaction or event in which the holders of our common stock have the right to receive any cash, securities or other property, the date fixed for determination of holders of stock entitled to receive such cash, securities or other property (whether such date is fixed by our board of directors or a committee thereof or by statute, contract or otherwise).

The Indenture does not require us to adjust the conversion rate for any of the transactions described in the clauses (1) through (5) above (other than for share splits or share combinations) if we make provision for each holder of the notes to participate in the transaction, at the same time as holders of our common stock participate, without conversion, as if such holder held a number of shares of our common stock equal to the conversion rate in effect on the record date or effective date, as the case may be, for such transaction, multiplied by the principal amount (expressed in thousands) of notes held by such holder.

If we issue rights, options or warrants that are only exercisable upon the occurrence of certain triggering events, then:

We will not adjust the conversion rate pursuant to the provisions described in clauses (1) through (5), inclusive, above unless the adjustment would result in a change of at least 1% in the then effective conversion rate. However, we will carry forward any adjustment that we would otherwise have to make and take that adjustment into account in any subsequent adjustment. However, all such deferred adjustments must be given effect immediately upon the earliest of the following: (i) when all such deferred adjustments

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would result in a change of at least 1% to the conversion rate; (ii) the conversion date of, or any VWAP trading day of an observation period for, any note; (iii) the date a fundamental change or make-whole fundamental change occurs; (iv) the date we call any notes for redemption; and (iv) March 15, 2023. The provisions described in this paragraph are referred to herein as the “1% provision.”

Adjustments to the conversion rate will be calculated to the nearest 1/10,000th.

To the extent permitted by law and the continued listing requirements of the NYSE, we may, from time to time, increase the conversion rate by any amount for a period of at least 20 business days or any longer period permitted or required by law, so long as the increase is irrevocable during that period and our board of directors (or a committee thereof) determines that the increase is in our best interests. We will send a notice of the increase to the trustee, the conversion agent and the holders at least 15 days before the day the increase commences. In addition, we may, but are not obligated to, increase the conversion rate as we determine to be advisable in order to avoid or diminish taxes to recipients of certain distributions.

To the extent that any future rights plan (i.e., a poison pill) adopted by us, is in effect, upon conversion of the notes, you will receive, in addition to any shares of our common stock that are otherwise due upon conversion, the rights under such future rights plan in respect of such shares of common stock, unless the rights have separated from our common stock at the time of conversion in accordance with the provisions of the applicable rights plan, in which case the conversion rate will be adjusted at the time of separation as if we had distributed to all holders of our common stock, shares of our capital stock, evidences of indebtedness, other assets, securities or property as described in clause (3)(a) under “— Adjustments to the Conversion Rate” above, subject to readjustment in the event of the expiration, termination or redemption of such rights. See “Description of capital stock.”

In the event of an adjustment to the conversion rate, the holders of the notes may, in certain circumstances, be deemed to have received a distribution subject to U.S. federal income tax as a dividend. This generally would occur, for example, if we adjust the conversion rate to compensate holders for cash dividends on our common stock and could also occur if we make other distributions of cash or property to our shareholders. See “Material U.S. Federal Income Tax Considerations.” Any applicable withholding taxes (including backup withholding) with respect to deemed dividends may be withheld from payments of interest and payments of cash or common stock upon conversion, repurchase or maturity of the notes or sales proceeds received by a holder, or if any withholding taxes (including backup withholding) are paid on behalf of a holder, those amounts may be set off against such payments of cash or common stock received by, or other funds or assets of, such holder.

Events That Will Not Result in Adjustment

The conversion rate will not be adjusted:

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Change in the Conversion Right Upon Certain Reclassifications, Business Combinations and Asset Sales

If we:

in each case pursuant to which our common stock would be converted into or exchanged for, or would constitute solely the right to receive, cash, securities or other property, including any combination thereof (such an event, a “common stock change event,” and such cash, securities or property, the “reference property,” and the amount and kind of reference property that a holder of one share of our common stock would be entitled to receive on account of such common stock change event (without giving effect to any arrangement not to issue or deliver a fractional portion of any security or other property), a “reference property unit”), then, notwithstanding anything to the contrary,

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If the common stock change event causes our common stock to be converted into, or exchanged for, the right to receive more than a single type of consideration (determined based in part upon any form of shareholder election), then the composition of the reference property unit will be deemed to be the weighted average of the types and amounts of consideration received by the holders of our common stock that affirmatively make such an election (or, if no such holders make an affirmative election, the weighted average of the types and amounts of consideration actually received by the holders of our common stock). We will notify holders of the weighted average as soon as practicable after such determination is made. We will agree in the Indenture not to become a party to any such common stock change event unless its terms are consistent with the foregoing.

A change in the conversion right such as this could substantially lessen or eliminate the value of the conversion right. For example, if a third party acquires us in a cash merger, each note would be convertible solely into cash and would no longer be potentially convertible into securities whose value could increase depending on our future financial performance, prospects and other factors. There is no precise, established definition of the phrase “all or substantially all of our consolidated property or assets” under applicable law. Accordingly, there may be uncertainty as to whether the provisions above would apply to a sale, transfer, lease, conveyance or other disposition of less than all of our consolidated property or assets.

Adjustment to the Conversion Rate Upon the Occurrence of a Make-Whole Fundamental Change

If, prior to the maturity date, there occurs any event or transaction (a “make-whole fundamental change”) that constitutes a “fundamental change” as defined below under “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” and determined after giving effect to any exceptions to or exclusions from such definition (including, for the avoidance of doubt, after giving effect to the provision described in the proviso immediately after clause (3) of the definition of “change of control”), but excluding the “non-ownership change of control” exception, then, as described below under “— The Increase in the Conversion Rate,” we will increase the conversion rate applicable to notes that are converted with a conversion date that occurs at any time from, and including, the effective date of the make-whole fundamental change to, and including, the 35th business day after the effective date of the make-whole fundamental change (or, if the make-whole fundamental change also constitutes a fundamental change, as described under “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change,” to, and including, the fundamental change repurchase date for that fundamental change). We refer to this period as the “make-whole conversion period.”

We will send to the trustee, the conversion agent and the holders notice of the effective date of any make-whole fundamental change in accordance with the procedures described above under the caption “— Conditions for Conversion — Conversion upon the Occurrence of Certain Corporate Transactions.”

The Increase in the Conversion Rate

In connection with the make-whole fundamental change, we will increase the conversion rate by reference to the table below, based on the date when the make-whole fundamental change becomes effective, which we refer to as the “effective date,” and the “applicable price” (as defined below). If the make-whole fundamental change is a transaction or series of related transactions described in clause (3) of the definition of “change of control” as defined below under “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change,” and the consideration (excluding cash payments for fractional shares or pursuant to statutory dissenters’ or appraisal rights) for shares of our common stock in the make-whole fundamental change consists solely of cash, then the “applicable price” will be the cash amount paid per share of our common stock in the make-whole fundamental change. In all other cases, the “applicable price” will be the average of the closing sale prices of our common stock for the five consecutive trading days immediately preceding, but excluding, the relevant effective date. Our board of directors (or a committee thereof) will make appropriate adjustments, in its good faith determination, to account for any

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adjustment to the conversion rate that becomes effective, or any event requiring an adjustment to the conversion rate where the “ex-dividend date” of the event occurs, at any time during those five consecutive trading days.

Upon surrender of notes for conversion in connection with a make-whole fundamental change, we will, at our option, satisfy our conversion obligation by delivering or paying, as the case may be, shares of our common stock (together with cash in lieu of any fractional share), cash or a combination of cash and shares of our common stock (together with cash in lieu of any fractional share) as described under “— Settlement Elections.” However, if the consideration for our common stock in any make-whole fundamental change is comprised entirely of cash, then, for any conversion of notes with a conversion date occurring on or after the effective date of such make- whole fundamental change, the conversion obligation will be calculated based solely on the applicable price for the transaction and will be deemed to be an amount, per $1,000 principal amount of converted notes, equal to the applicable conversion rate (including any adjustment as described in this section), multiplied by such applicable price. In such event, the cash due upon conversion will be determined and paid to holders in cash on the second business day following such conversion date.

The following table sets forth the number of additional shares per $1,000 principal amount of notes that will be added to the conversion rate applicable to the notes that are converted during the make-whole conversion period. The increased conversion rate will be used to determine the consideration due upon conversion, as described under “— Settlement Upon Conversion” above. If an event occurs that requires an adjustment to the conversion rate, we will, on the date we must adjust the conversion rate, adjust each applicable price set forth in the first column of the table below at the same time the conversion rate is so adjusted by multiplying the applicable price in effect immediately before the adjustment by a fraction:

In addition, we will adjust the number of additional shares in the table below at the same time, in the same manner in which, and for the same events for which, we must adjust the conversion rate as described under “— Adjustments to the Conversion Rate.”

The exact applicable price and effective date may not be as set forth in the table above, in which case:

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However, we will not increase the conversion rate as described above to the extent the increase will cause the conversion rate to exceed                  shares of our common stock per $1,000 principal amount of notes. We will adjust this maximum conversion rate in the same manner in which, and for the same events for which, we must adjust the conversion rate as described under “— Adjustments to the Conversion Rate.”

Our obligation to increase the conversion rate as described above could be considered a penalty, in which case its enforceability would be subject to general principles of reasonableness of economic remedies.

Optional Redemption

Prior to March 15, 2021, the notes will not be redeemable. We may, at our option, redeem (a “conversion price trigger redemption”) some or all of the notes on a redemption date that occurs on or after March 15, 2021 if the closing sale price of our common stock has been at least 130% of the conversion price then in effect on (x) the trading day immediately preceding the date on which we provide a redemption notice and (y) for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which we provide such redemption notice. The redemption price for each $1,000 principal amount of notes to be redeemed (the “conversion price trigger redemption price”) shall be payable in cash and shall be equal to the sum of (i) 100% of the principal amount of the notes to be redeemed, plus (ii) accrued and unpaid interest, if any, to, but excluding, the redemption date, plus (iii) the make-whole premium (as defined below). We must make these make-whole premium payments on all notes called for redemption prior to September 15, 2023, including notes subject to redemption that are converted after the date we delivered the notice of redemption.

The “make-whole premium” means, in respect of any notes called for a conversion price trigger redemption, the amount equal to the present value of the remaining scheduled payments of interest that would have been made on such notes to be redeemed had such notes remained outstanding from the relevant redemption date to, and including, September 15, 2023 (excluding interest accrued to, but excluding, such redemption date, which shall otherwise be payable pursuant to clause (ii) of the definition of conversion price trigger redemption price set forth above), with such present value of the remaining interest payments computed using a discount rate per annum equal to the reference discount rate (as defined below) plus 50 basis points.

The “reference discount rate” means, in respect of any make-whole premium, the yield to maturity of United States Treasury securities with a constant maturity (as compiled and published in the most recent Federal Reserve Statistical Release H.15 (519) that has become publicly available at least two business days prior to the relevant redemption date (or, if such Statistical Release is no longer published, any publicly available source of similar market data)) most nearly equal to the period from such redemption date to the maturity date; provided, however, that if the period from such redemption date to the maturity date is less than one year, the weekly average yield on actively traded United States Treasury securities adjusted to a constant maturity of one year will be used. Any such reference discount rate shall be obtained by us.

If the redemption date occurs after a record date and on or prior to the immediately succeeding interest payment date, (i) accrued and unpaid interest shall be paid on such interest payment date to the record holder on the relevant record date, (ii) the redemption price will not include any accrued and unpaid interest, and (iii) the make-whole premium shall equal the present value of all remaining scheduled payments of interest on such notes, starting with the next interest payment date for which interest has not been provided for (but otherwise calculated as described in the definition of make-whole premium).

We will provide notice of redemption to each holder of notes to be redeemed at least 45, but no more than 65, scheduled trading days before the related redemption date. If the redemption notice is given and

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funds are deposited as required, then interest will cease to accrue on and after the redemption date on those notes or portions of notes called for redemption (other than as described in clause (i) of the immediately preceding paragraph).

Once we have called the notes for redemption, notes or portions of notes will be convertible by the holder until the close of business on the second business day prior to the redemption date, unless we fail to pay the redemption price.

If we decide to redeem fewer than all of the outstanding notes, then, subject to applicable DTC rules, the trustee will select the notes to be redeemed (in principal amounts of $1,000 or integral multiples thereof) by lot, on a pro rata basis or by another method the trustee considers fair and appropriate. If the trustee selects a portion of a holder’s notes for partial redemption and the holder converts a portion of its notes, the converted portion will be deemed to be from the portion selected for redemption.

We may not redeem any notes if the principal amount of the notes has been accelerated and such acceleration has not been rescinded on or before the redemption date (including as a result of the payment of the related redemption price and any related interest described above on the redemption date).

Holders May Require Us to Repurchase their Notes Upon A Fundamental Change

If a “fundamental change,” as described below, occurs, each holder will have the right, at its option, subject to the terms and conditions of the Indenture, to require us to repurchase for cash all or any portion of the holder’s notes in integral multiples of $1,000 principal amount, at a price equal to 100% of the principal amount of the notes to be repurchased, plus, except as described below, any accrued and unpaid interest, if any, to, but excluding, the “fundamental change repurchase date,” as described below. However, if the fundamental change repurchase date is after a record date for the payment of an installment of interest and on or before the related interest payment date, then the full amount of interest due on that interest payment date will be payable, on that interest payment date, to the holder of record at the close of business on the record date, and the fundamental change repurchase price will not include any accrued and unpaid interest.

We must repurchase the notes on a date of our choosing, which we refer to as the “fundamental change repurchase date.” However, the fundamental change repurchase date shall be no later than 35 days, and no earlier than 20 days, after the date we send the relevant notice of the fundamental change, as described below.

Within 20 business days after the occurrence of a fundamental change, we must send to all holders of notes, and to beneficial owners as required by applicable law, a notice regarding the fundamental change. The notice must state, among other things:

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To exercise the fundamental change repurchase right with respect to any certificated notes, a holder must deliver the notes to be repurchased, duly endorsed for transfer, together with a written fundamental change repurchase notice to the paying agent no later than the close of business on the second business day immediately preceding the fundamental change repurchase date. This written notice must state:

A holder may withdraw any fundamental change repurchase notice by delivering to the paying agent a written notice of withdrawal prior to the close of business on the second business day immediately preceding the fundamental change repurchase date. The notice of withdrawal must state:

If the notes are not in certificated form, the above notices must instead comply with appropriate DTC procedures no later than the close of business on the second business day immediately preceding the fundamental change repurchase date.

We will pay the fundamental change repurchase price no later than the later of the fundamental change repurchase date and the time of book-entry transfer or delivery of the note, together with necessary endorsements.

For a discussion of certain tax considerations applicable to a holder upon the exercise of the repurchase right, see “Material U.S. Federal Income Tax Considerations.”

If the paying agent holds on the fundamental change repurchase date money sufficient to pay the fundamental change repurchase price due on all notes surrendered for repurchase in accordance with the terms of the Indenture, then, on and after the fundamental change repurchase date, such notes will cease to be outstanding and (except as described in the last sentence of the first paragraph under this “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” section) interest on such notes will cease to accrue, whether or not the book-entry transfer of the notes is made or whether or not the holder delivers the notes to the paying agent. Thereafter, all other rights of the relevant holders terminate, other than the right to receive the fundamental change repurchase price upon book-entry transfer or delivery of the note (and, if applicable, the right to receive interest).

A “fundamental change” will be deemed to occur upon the occurrence of a “change of control” or a “termination of trading.”

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A “change of control” generally will be deemed to occur at such time as:

provided, however, that a transaction or event described in clauses (1) or (2) above will not constitute a change of control (and for the avoidance of doubt, we are not required to deliver the notice incidental thereto) if at least 90% of the consideration received or to be received by the holders of our common stock (excluding cash payments for fractional shares or pursuant to statutory dissenters’ or appraisal rights), in connection with such transaction or event, consists of common equity listed (or depositary receipts representing common equity, which depositary receipts are listed) on any of The New York Stock Exchange, The NASDAQ Global Market or The NASDAQ Global Select Market (or any of their respective successors), or that will be so listed when issued or exchanged in connection with such transaction or event, and such transaction or event constitutes a common stock change event whose reference property consists of such consideration.

For the purposes of this definition, any transaction or event described in both clause (1) and in clause (2)(i) or (2)(ii) above will be deemed to occur solely pursuant to clause (2) above.

There is no precise, established definition of the phrase “all or substantially all of our consolidated property or assets” under applicable law. Accordingly, there may be uncertainty as to whether a transfer,

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lease, conveyance or other disposition of less than all of our consolidated property or assets would permit a holder to exercise its right to have us repurchase its notes in accordance with the fundamental change provisions described above.

A “termination of trading” is deemed to occur if shares of our common stock are not listed for trading on NYSE, The NASDAQ Global Select Market or The NASDAQ Global Market (or any of their respective successors).

We may not have the financial resources, and we may not be able to arrange for financing, to pay the fundamental change repurchase price for all notes holders have elected to have us repurchase. Furthermore, the terms of our existing or future indebtedness may limit our ability to pay the repurchase price to repurchase notes. Our failure to repurchase the notes when required would result in an event of default with respect to the notes. The exercise by holders of the notes of their right to require us to repurchase their notes upon a fundamental change could cause a default under our other outstanding indebtedness, even if the fundamental change itself does not.

Furthermore, holders may not be entitled to require us to repurchase their notes in certain circumstances involving a significant change in the composition of our board of directors that does not occur in connection with a transaction that otherwise constitutes a fundamental change.

We may in the future enter into transactions, including recapitalizations, that would not constitute a fundamental change but that would increase our debt or otherwise adversely affect holders. The Indenture for the notes does not restrict our or our subsidiaries’ ability to incur indebtedness, including senior or secured indebtedness. Our incurrence of additional indebtedness could adversely affect our ability to service our indebtedness, including the notes.

In addition, the fundamental change repurchase feature of the notes would not necessarily afford holders of the notes protection in the event of highly leveraged or other transactions involving us that may adversely affect holders of the notes. Furthermore, the fundamental change repurchase feature of the notes may in certain circumstances deter or discourage a third party from acquiring us, even if the acquisition may be beneficial to you.

In connection with any fundamental change offer, we will, to the extent applicable:

Notwithstanding anything to the contrary herein, to the extent that compliance with this “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change” would result in a violation of any federal or state securities laws or other applicable laws or regulations, we will comply with the applicable securities laws and regulations and will not be deemed to have breached our obligations by virtue of the conflict.

No notes may be repurchased by us at the option of the holders upon a fundamental change if the principal amount of the notes has been accelerated and such acceleration has not been rescinded on or before the fundamental change repurchase date (including as a result of the payment of the related fundamental change repurchase price and any related interest described above on the fundamental change repurchase date).

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Consolidation, Merger and Sale of Assets

The Indenture prohibits us from consolidating with, or merging with or into, or selling, transferring, leasing, conveying or otherwise disposing of all or substantially all of our consolidated property or assets to, another person, whether in a single transaction or series of related transactions, unless, among other things:

When the successor assumes all of our obligations under an Indenture, except in the case of a lease, our obligations under the Indenture will terminate.

Some of the transactions described above could constitute a fundamental change that permits holders to require us to repurchase their notes, as described under “— Holders May Require Us to Repurchase their Notes Upon A Fundamental Change.”

There is no precise, established definition of the phrase “all or substantially all of our consolidated property or assets” under applicable law. Accordingly, there may be uncertainty as to whether the provisions above would apply to a sale, transfer, lease, conveyance or other disposition of less than all of our consolidated property or assets.

Events of Default

The following constitute defaults under the Indenture, subject to any additional limitations and qualifications included in the Indenture:

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The foregoing will constitute events of default whatever the reason for any such event of default and whether it is voluntary or involuntary or is effected by operation of law or pursuant to any judgment, decree or order of any court or any order, rule or regulation of any administrative or governmental body.

If a default under the Indenture occurs and is continuing and is known to the trustee, the trustee must send to each holder of the notes notice of the default within 90 days after it occurs. The trustee may withhold notice to the holders of the notes of a default (except defaults in the payment of the principal of or interest on the notes) if the trustee considers it to be in the interest of the holders of the notes to withhold this notice.

If an event of default (other than an event of default relating to certain events of bankruptcy, insolvency or reorganization of us) occurs and continues, the trustee or the holders of at least 25% in principal amount of the outstanding notes may declare the principal and accrued and unpaid interest on the outstanding notes to be immediately due and payable. In case of certain events of bankruptcy, insolvency or reorganization involving us (and not solely involving one or more of our significant subsidiaries), the principal and accrued and unpaid interest on the notes will automatically become immediately due and payable. Under certain circumstances, the holders of a majority in principal amount of the outstanding notes may rescind such acceleration with respect to the notes and, as is discussed below, waive these past defaults.

The holders of a majority in principal amount of outstanding notes will have the right to direct the time, method and place of any proceedings for any remedy available to the trustee or of exercising any trust or power conferred on the trustee, subject to limitations specified in the Indenture. The trustee, however, may refuse to follow any direction that conflicts with law or the Indenture or that the trustee determines is unduly prejudicial to the rights of any other holder of the notes or that would involve the trustee in personal liability. Prior to taking any action under the Indenture, the trustee will be entitled to indemnification satisfactory to it in its sole discretion against all losses and expenses caused by taking or not taking such action.

The holders of a majority in principal amount of outstanding notes may, by notice to the trustee, waive any past defaults under the Indenture, except a default due to the non-payment of principal or interest, if any, a failure to convert any notes into common stock when required pursuant to the terms of the Indenture, a default arising from our failure to redeem or repurchase any notes when required pursuant to the terms of the Indenture or a default in respect of any covenant that cannot be amended without the consent of each holder affected.

No holder of the notes may pursue any remedy under the Indenture, except in the case of a default due to the non-payment of principal or interest, on the notes, unless:

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The Indenture requires us (i) every year to deliver to the trustee a statement as to performance of our obligations under the Indenture and as to any default and (ii) to deliver to the trustee prompt notice of any default.

A default in the payment of the notes, or a default with respect to the notes that causes them to be accelerated, may give rise to a cross-default under our existing borrowing arrangements.

Notwithstanding anything to the contrary described above, we may elect that the sole remedy for any event of default (a “reporting event of default”) pursuant to clause (5) above arising from our failure to comply with our obligations described below under the caption “— Exchange Act Reports” will, for each of the first 180 calendar days on which a reporting event of default has occurred and is continuing, consist exclusively of the accrual of special interest on the notes. If we have made such an election, then (i) the notes will be subject to acceleration as described above on account of the relevant reporting event of default from, and including, the 181st calendar day on which a reporting event of default has occurred and is continuing or if we fail to pay any accrued and unpaid special interest when due; and (ii) special interest will cease to accrue on any notes from, and including, such 181st calendar day.

Any special interest that accrues on a note will be payable on the same dates and in the same manner as the stated interest on such note and will accrue at a rate per annum equal to 0.25% of the principal amount thereof. For the avoidance of doubt, any special interest that accrues on a note will be in addition to the stated interest that accrues on such note. Each reference in this “Description of Notes” section to interest on any note includes special interest, if any, that has accrued on such note, unless the context requires otherwise.

To make the election to pay special interest as described above, we must provide notice of such election to noteholders before the date on which each reporting event of default first occurs. The notice will also, among other things, briefly describe the periods during which and rate at which special interest will accrue and the circumstances under which the notes will be subject to acceleration on account of such reporting event of default.

Exchange Act Reports

We will send to the trustee copies of all reports that we are required to file with or furnish to the SEC pursuant to Section 13(a) or 15(d) of the Exchange Act within 15 calendar days after the date that we are required to so file or furnish the same (after giving effect to all applicable grace periods under the Exchange Act). However, we need not send to the trustee any material for which we have received, or are seeking in good faith and have not been denied, confidential treatment by the SEC. Any report that we file with or furnish to the SEC through the EDGAR system (or any successor thereto) will be deemed to be sent to the trustee at the time such report is so filed or furnished via the EDGAR system (or such successor).

Amendment and Modification

The consent of the holders of a majority in principal amount of the outstanding notes is required to modify or amend the Indenture. However, a modification or amendment requires the consent of the holder of each outstanding note affected by such modification or amendment if it would:

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However, notwithstanding anything to the contrary described above, we and the trustee may modify certain provisions of the Indenture or the notes without the consent of the holders of the notes, including to:

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The holders of a majority in aggregate principal amount of the outstanding notes may, on behalf of all the holders of all notes, waive all compliance by us with provisions in the Indenture, as detailed in the Indenture (other than the provisions of the Indenture whose modification or amendment otherwise requires the consent of the holder of each outstanding note affected by such modification or amendment as described above); or waive any past default or event of default under the Indenture and its consequences, except a default or event of default in the payment of any amount due, or in the obligation to deliver consideration upon conversion or with respect to any note or in respect of any provision which under the Indenture cannot be modified or amended without the consent of the holder of each outstanding note affected.

Satisfaction and Discharge

We may satisfy and discharge our obligations under the Indenture by delivering to the trustee for cancellation all outstanding notes or by depositing with the trustee or delivering to the holders, as applicable, after all then-outstanding notes have become due and payable, whether at the stated maturity, or any redemption date or fundamental change repurchase date, or upon conversion or otherwise, cash (or, if applicable with respect to any conversion shares of our common stock or other reference property) sufficient to pay all of the outstanding notes and paying all other sums payable under the Indenture by us. Such discharge is subject to terms contained in the Indenture.

Calculations in Respect of Notes

We will be responsible for making all calculations called for under the notes. These calculations include, but are not limited to, determinations of the market prices of our common stock, the amount of accrued interest payable on the notes, the closing sale prices, the volume-weighted average prices, the conversion price of the notes, any conversion values, daily settlement amounts and the conversion rates of the notes, including adjustments to any of the foregoing required by the Indenture. We will make all these calculations in good faith, and, absent manifest error, our calculations will be final and binding on holders of notes. We will provide a schedule of our calculations to each of the trustee and the conversion agent, and each of the trustee and the conversion agent is entitled to rely upon the accuracy of our calculations without independent verification. The trustee will forward our calculations to any holder of notes upon the request of that holder.

No Personal Liability of Directors, Officers, Employees or Shareholders

None of our past, present or future directors, officers, employees or shareholders, as such, will have any liability for any of our obligations under the notes or the Indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a note, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the notes. 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.

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Unclaimed Money

If money deposited with the trustee or paying agent for the payment of principal of, or accrued and unpaid interest on, the notes remains unclaimed for two years, the trustee and paying agent will pay the money back to us upon our written request. However, the trustee and paying agent have the right to withhold paying the money back to us until they publish (in no event later than five days after we request repayment) in a newspaper of general circulation in the City of New York, or send to each holder, a notice stating that the money will be paid back to us if unclaimed after a date no less than 30 days from the publication or sending, in each case at our cost. After the trustee or paying agent pays the money back to us, holders of notes entitled to the money must look to us for payment as general creditors, subject to applicable law, and all liability of the trustee and the paying agent with respect to the money will cease.

Replacement of Notes

We will replace mutilated, lost, destroyed or stolen notes at the holder’s expense upon delivery to the trustee of the mutilated notes or evidence of the loss, destruction or theft of the notes satisfactory to the trustee and us. In the case of a lost, destroyed or stolen note, we or the trustee may require, at the expense of the holder, indemnity (including in the form of a bond) satisfactory to us and the trustee.

Trustee, Conversion Agent, Paying Agent and Transfer Agent

We have appointed The Bank of New York Mellon Trust Company, N.A., as the trustee under the Indenture, and as paying agent, conversion agent, note registrar and custodian for the notes. The trustee or its affiliates may also provide banking and other services to us in the ordinary course of their business.

The transfer agent for our common stock is EQ Shareowner Services.

Listing and Trading

We do not intend to apply for listing of the notes on any securities exchange or to arrange for their quotation on any interdealer quotation system. Our common stock is listed on NYSE under the ticker symbol “HLX.”

Book-Entry Delivery and Form

General

The notes offered hereby will be issued in registered, global form in denominations of integral multiples of $1,000 principal amount. The notes will be issued on the issue date therefor only against payment in immediately available funds.

The notes offered hereby initially will be represented by one or more permanent global certificates in definitive, fully registered form without interest coupons, which we refer to as the “global securities.”

The global securities will be deposited upon issuance with the trustee as custodian for DTC in New York, New York, and registered in the name of DTC or its nominee for credit to an account of a direct or indirect participant in DTC (including the Euroclear Bank S.A./N.V. (“Euroclear”) or Clearstream Banking, société anonyme (“Clearstream”)), as described below under “— Depositary Procedures.”

Except as set forth below, the global securities may be transferred, in whole and not in part, only to DTC, to another nominee of DTC or to a successor of DTC or its nominee. Beneficial interests in the global securities may not be exchanged for notes in certificated form except in the limited circumstances described below under “— Exchange of Book-Entry Securities for Certificated Securities.”

Transfers of beneficial interests in the global securities will be subject to the applicable rules and procedures of DTC and its direct or indirect participants (including, if applicable, those of Euroclear and Clearstream), which may change from time to time.

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Depositary Procedures

The following description of the operations and procedures of DTC, Euroclear and Clearstream is provided solely as a matter of convenience. These operations and procedures are solely within the control of the respective settlement systems and are subject to changes by them. We take no responsibility for these operations and procedures and urge investors to contact the systems or their participants directly to discuss these matters.

DTC is a limited-purpose trust company created to hold securities for its participating organizations, referred to as “participants,” and facilitate the clearance and settlement of transactions in those securities between DTC’s participants through electronic book-entry changes in accounts of its participants. DTC’s participants include securities brokers and dealers (including the underwriters), banks, trust companies, clearing corporations and certain other organizations. Access to DTC’s system is also available to other entities such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a DTC participant, either directly or indirectly, which entities are referred to as “indirect participants.” Persons who are not DTC participants may beneficially own securities held by or on behalf of DTC only through participants or indirect participants. DTC has no knowledge of the identity of beneficial owners of securities held by or on behalf of DTC. DTC’s records reflect only the identity of its participants to whose accounts securities are credited. The ownership interests and transfer of ownership interests of each beneficial owner of each security held by or on behalf of DTC are recorded on the records of DTC’s participants and indirect participants.

Pursuant to procedures established by DTC:

Investors in the global securities may hold their interests therein directly through DTC, if they are participants in such system, or indirectly through organizations (including Euroclear and Clearstream) that are participants or indirect participants in such system. Euroclear and Clearstream will hold interests in the notes on behalf of their participants through customers’ securities accounts in their respective names on the books of their respective depositaries. The depositaries, in turn, will hold interests in the notes in customers’ securities accounts in the depositaries’ names on the books of DTC.

All interests in a global security, including those held through Euroclear or Clearstream, will be subject to the procedures and requirements of DTC. Those interests held through Euroclear or Clearstream will also be subject to the procedures and requirements of these systems. The laws of some jurisdictions require that certain persons take physical delivery of certificates evidencing securities they own. Consequently, the ability to transfer beneficial interests in a global security to such persons will be limited to that extent. Because DTC can act only on behalf of its participants, which in turn act on behalf of indirect participants, the ability of beneficial owners of interests in a global security to pledge such interests to persons or entities that do not participate in the DTC system, or otherwise take actions in respect of such interests, may be affected by the lack of a physical certificate evidencing such interests. For certain other restrictions on the transferability of the notes, see “— Exchange of Book-Entry Securities for Certificated Securities.”

Except as described below, owners of interests in the global security will not have notes registered in their names, will not receive physical delivery of notes in certificated form and will not be considered the registered owners or holders thereof under the Indenture for any purpose. All references herein to “holders” refers to the registered holders of the notes.

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Payments in respect of the principal of, and interest on, a global security registered in the name of DTC or its nominee will be payable by the trustee (or the paying agent if other than the trustee) to DTC in its capacity as the registered holder under the Indenture. We and the trustee will treat the persons in whose names the notes, including the global securities, are registered as the owners thereof for the purpose of receiving such payments and for any and all other purposes whatsoever. Consequently, neither we nor the trustee or any of our respective agents has or will have any responsibility or liability for:

DTC has advised us that its current practice, upon receipt of any payment in respect of securities such as the notes (including principal and interest), is to credit the accounts of the relevant participants with the payment on the payment date in amounts proportionate to their respective holdings in the principal amount of the relevant security as shown on the records of DTC, unless DTC has reason to believe it will not receive payment on such payment date. Payments by the participants and the indirect participants to the beneficial owners of notes will be governed by standing instructions and customary practices and will be the responsibility of the participants or the indirect participants and will not be the responsibility of DTC, the trustee or us. Neither we nor the trustee will be liable for any delay by DTC or any of its participants in identifying the beneficial owners of the notes, and we and the trustee may conclusively rely on and will be protected in relying on instructions from DTC or its nominee for all purposes.

Transfers between participants in DTC will be effected in accordance with DTC’s procedures, and will be settled in same day funds, and transfers between participants in Euroclear and Clearstream will be effected in accordance with their respective rules and operating procedures.

Cross-market transfers between participants in DTC, on the one hand, and Euroclear or Clearstream participants, on the other hand, will be effected through DTC in accordance with DTC’s rules on behalf of Euroclear or Clearstream, as the case may be, by their depositaries. Cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in that system in accordance with the rules and procedures and within the established deadlines (Brussels time) of that system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its respective depositaries to take action to effect final settlement on its behalf by delivering or receiving interests in the relevant global security in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Euroclear and Clearstream participants may not deliver instructions directly to the depositaries for Euroclear or Clearstream.

Because of time zone differences, the securities account of a Euroclear or Clearstream participant purchasing an interest in a global security from a participant in DTC will be credited and reported to the relevant Euroclear or Clearstream participant during the securities settlement processing day (which must be a business day for Euroclear and Clearstream) immediately following the settlement date of DTC. DTC has advised us that cash received in Euroclear or Clearstream as a result of sales of interests in a global security by or through a Euroclear or Clearstream participant to a participant in DTC will be received with value on the settlement date of DTC but will be available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC’s settlement date.

DTC has advised us that it will take any action permitted to be taken by a holder of notes only at the direction of one or more participants to whose account with DTC interests in the global securities are

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credited and only in respect of such portion of the aggregate principal amount of the notes as to which such participant or participants has or have given such direction.

Although DTC, Euroclear and Clearstream have agreed to the foregoing procedures to facilitate transfers of interests in the global securities among participants in DTC, Euroclear and Clearstream, they are under no obligation to perform or to continue to perform such procedures, and the procedures may be discontinued at any time. None of us, any underwriter or the trustee will have any responsibility for the performance by DTC, Euroclear or Clearstream or their respective participants or indirect participants of their respective obligations under the rules and procedures governing their operations.

The information in this section concerning DTC, Euroclear and Clearstream and their book-entry systems has been obtained from sources that we believe to be reliable, but neither we nor any underwriter takes any responsibility for the accuracy thereof.

Exchange of Book-Entry Securities for Certificated Securities

The global securities are exchangeable for certificated securities in definitive, fully registered form without interest coupons only if:

Governing Law

The Indenture and the notes will be governed by and construed in accordance with the laws of the State of New York.

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DESCRIPTION OF OTHER INDEBTEDNESS

The following is a summary of certain of our indebtedness that will be outstanding following the consummation of this offering. The summary below does not purport to be complete and is qualified in its entirety by reference to the applicable documents, copies of which have been filed with the SEC and which we will provide you upon request. See the sections entitled “Where You Can Find More Information.”

Credit Agreement

On June 30, 2017, we entered into an Amended and Restated Credit Agreement (the “Credit Agreement”) with a group of lenders led by Bank of America, N.A. (“Bank of America”). The amended and restated credit facility is comprised of a $100 million term loan (the “Term Loan”) and a revolving credit facility (the “Revolving Credit Facility”) of up to $150 million (the “Revolving Loans”). The Revolving Credit Facility permits us to obtain letters of credit up to a sublimit of $25 million. Pursuant to the Credit Agreement, subject to existing lender participation and/or the participation of new lenders, and subject to standard conditions precedent, we may request aggregate commitments up to $100 million with respect to an increase in the Revolving Credit Facility, additional term loans, or a combination thereof. The $100 million proceeds from the Term Loan as well as cash on hand were used to repay the approximately $180 million term loan then outstanding under the credit facility prior to its June 2017 amendment and restatement. As of December 31, 2017, we had no borrowings under the Revolving Credit Facility and our available borrowing capacity under that facility, based on the applicable leverage ratio covenant, totaled $81.6 million, net of $3.0 million of letters of credit issued under that facility.

The Term Loan and the Revolving Loans (together, the “Loans”), at our election, bear interest either in relation to Bank of America’s base rate or to a LIBOR rate. The Term Loan or portions thereof bearing interest at the base rate will bear interest at a per annum rate equal to the base rate plus 3.25%. The Term Loan or portions thereof bearing interest at a LIBOR rate will bear interest per annum at the LIBOR rate selected by us plus a margin of 4.25%. The Revolving Loans or portions thereof bearing interest at the base rate will bear interest at a per annum rate equal to the base rate plus a margin ranging from 1.75% to 3.25%. The Revolving Loans or portions thereof bearing interest at a LIBOR rate will bear interest per annum at the LIBOR rate selected by us plus a margin ranging from 2.75% to 4.25%. A letter of credit fee is payable by us equal to its applicable margin for LIBOR rate Loans times the daily amount available to be drawn under the applicable letter of credit. Margins on the Revolving Loans will vary in relation to the Consolidated Total Leverage Ratio (as defined below) provided for in the Credit Agreement. We also pay a fixed commitment fee of 0.50% per annum on the unused portion of our Revolving Credit Facility.

The Term Loan principal is required to be repaid in quarterly installments totaling 5% in the first loan year, 10% in the second loan year and 15% in the third loan year, with a balloon payment at maturity. Installment amounts are subject to adjustment for any prepayments on the Term Loan. We may elect to prepay amounts outstanding under the Term Loan without premium or penalty, but may not reborrow any amounts prepaid. We may prepay amounts outstanding under the Revolving Credit Facility without premium or penalty, and may reborrow any amounts prepaid up to the amount of the Revolving Credit Facility. The Loans mature on June 30, 2020.

The Credit Agreement and the other documents entered into in connection with the Credit Agreement include terms and conditions, including covenants, which we consider customary for this type of transaction. The covenants include certain restrictions on our and our subsidiaries’ ability to grant liens, incur indebtedness, make investments, merge or consolidate, sell or transfer assets, pay dividends and make capital expenditures. In addition, the Credit Agreement obligates us to meet minimum financial ratio requirements of EBITDA to interest charges (“Consolidated Interest Coverage Ratio”) and funded debt to EBITDA (“Consolidated Total Leverage Ratio”), and provided that if there are no Loans outstanding, the funded debt ratio requirement permits us to offset a certain amount of cash against the funded debt used in the calculation (“Consolidated Net Leverage Ratio”). After the initial Term Loan is repaid in full, if there are any Loans outstanding including unreimbursed draws under letters of credit issued under the Revolving

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Credit Facility, we are also required to ensure that the ratio of our total secured indebtedness to EBITDA (“Consolidated Secured Leverage Ratio”) does not exceed the maximum permitted ratio. The Credit Agreement also obligates us to maintain certain cash levels depending on the type of indebtedness outstanding. These financial covenant requirements are detailed as follows:

The minimum required Consolidated Interest Coverage Ratio: