UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549
SCHEDULE 13G
Under the Securities and Exchange Act of 1934
(Amendment No. )*
Summit Midstream Partners, LP
------------------------------------------------------------------
(Name of Issuer)
Common Units Representing Limited Partner Interests
------------------------------------------------------------------
(Title of Class of Securities)
866142102
------------------------------------------------------------------
(CUSIP Number)
December 31, 2015
------------------------------------------------------------------
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to
which this Schedule is filed:
[X] Rule 13d-1 (b)
[ ] Rule 13d-1 (c)
[ ] Rule 13d-1 (d)
* The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect to
the subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided
in a prior cover page.
The information required in the remainder of this cover page
shall not be deemed to be "filed" for the purpose of Section 18
of the Securities Exchange Act of 1934 ("Act") or otherwise
subject to the liabilities of that section of the Act, but shall
be subject to all other provisions of the Act (however, see
the Notes.)
CUSIP NO. 866142102 13G
1 Name of Reporting Person
Advisory Research Inc.
------------------------------------------------------------------
2 Check the Appropriate Box if a Member of a Group (a) [ ]
(b) [ ]
------------------------------------------------------------------
3 SEC Use Only
------------------------------------------------------------------
4 Citizenship or Place of Organization
Delaware
------------------------------------------------------------------
Number of Sole Voting Power
5 2,396,008
Shares
-----------------------------------------------
Beneficially
6 Shared Voting Power
Owned By 0
-----------------------------------------------
Each
7 Sole Dispositive Power
Reporting 2,434,948
-----------------------------------------------
Person
8 Shared Dispositive Power
With 0
------------------------------------------------------------------
9 Aggregate Amount Beneficially Owned by Each Reporting Person
2,434,948
------------------------------------------------------------------
10 Check if the Aggregate Amount in Row (9) Excludes Certain
Shares [ ]
------------------------------------------------------------------
11 Percent of Class Represented by Amount in Row (9)
5.8%
------------------------------------------------------------------
12 Type of Reporting Person
IA
------------------------------------------------------------------
CUSIP NO. 866142102 13G
1 Name of Reporting Person:
Piper Jaffray Companies
------------------------------------------------------------------
2 Check the Appropriate Box if a Member of a Group (a) [ ]
(b) [ ]
------------------------------------------------------------------
3 SEC Use Only
------------------------------------------------------------------
4 Citizenship or Place of Organization
Delaware
------------------------------------------------------------------
Number of
5 Sole Voting Power
Shares 0
-----------------------------------------------
Beneficially
6 Shared Voting Power
Owned By 2,396,008
-----------------------------------------------
Each
7 Sole Dispositive Power
Reporting 0
-----------------------------------------------
Person
8 Shared Dispositive Power
With 2,434,948
------------------------------------------------------------------
9 Aggregate Amount Beneficially Owned by Each Reporting Person
2,434,948
------------------------------------------------------------------
10 Check if the Aggregate Amount in Row (9) Excludes Certain
Shares [ ]
------------------------------------------------------------------
11 Percent of Class Represented by Amount in Row (9)
5.8%
------------------------------------------------------------------
12 Type of Reporting Person
HC
------------------------------------------------------------------
Item 1 (a) Name of Issuer:
Summit Midstream Partners, LP
(b) Name of Issuer's Principal Executive Offices:
1790 Hughes Landing Boulevard, Suite 500
The Woodlands, Texas 77380
Item 2 (a) Person Filing:
(i) Advisory Research, Inc.
(ii) Piper Jaffray Companies
(b) Address:
(i) Advisory Research, Inc.
180 N. Stetson Ave., Suite 5500
Chicago, IL 60601
(ii) Piper Jaffray Companies
800 Nicollet Mall Suite 800
Minneapolis, MN 55402
(c) Citizenship:
Advisory Research Inc. and Piper Jaffray Companies:
Delaware
(d) Title of Class of Securities:
Common Units Representing Limited Partner Interests
(e) CUSIP Number: 866142102
Item 3 If this statement is filed pursuant to sections
240.13d-1(b) or 240.13d-2(b) or (c), check whether the
person filing is a:
(i) Advisory Research, Inc. is an investment advisor in
accordance with section 240.13d-1(b)(1)(ii)(E)
(ii) Piper Jaffray Companies is a parent holding company
or control person in accordance with section
240.13d-1(b)(1)(ii)(G)
Item 4 Ownership
(a) Amount Beneficially Owned:
(i) Advisory Research, Inc.: 2,434,948
(ii) Piper Jaffray Companies: 2,434,948
(b) Percent of Class
(i) Advisory Research, Inc.: 5.8%
(ii) Piper Jaffray Companies: 5.8%
(c) Number of shares as to which reporting person has:
(1) Sole power to vote or direct vote:
(i) Advisory Research, Inc.: 2,396,008
(ii) Piper Jaffray Companies: 0
(2) Shared power to vote or direct the vote:
(i) Advisory Research, Inc.: 0
(ii) Piper Jaffray Companies: 2,396,008
(3) Sole power to dispose or to direct disposition of:
(i) Advisory Research, Inc.: 2,434,948
(ii) Piper Jaffray Companies: 0
(4) Shared power to dispose or to direct the disposition of:
(i) Advisory Research, Inc.: 0
(ii) Piper Jaffray Companies: 2,434,948
Item 5 Ownership of Five Percent or Less of a Class:
If this statement is being filed to report the fact
that as of the date hereof the reporting person has
ceased to be the beneficial owner of more than five
percent of the class of securities, check the
following [ ]
Not Applicable
Item 6 Ownership of More than Five Percent on Behalf of Another
Person:
Not Applicable
Item 7 Identification and Classification of the Subsidiary
Which Acquired the Security being Reported on by the
Parent Holding Company:
Not Applicable
Item 8 Identification and Classification if Members of
the Group:
Not Applicable
Item 9 Notice of Dissolution of Group:
Not Applicable
Item 10 Certification
By signing below I certify that, to the best of my knowledge and belief,
the securities referred to above were acquired and are held in the ordinary
course of business and were not acquired and are not held for the purpose of
or with the effect of changing or influencing the control of the issuer of
the securities and were not acquired and are not held in connection with or
as a participant in any transaction having that purpose or effect.
In accordance with Rule 13d-4 of the Securities Exchange Act of 1934, each
of the persons filing this statement expressly disclaim the beneficial
ownership of the securities covered by this statement and the filing of
this report shall not be construed as an admission by such persons that
they are the beneficial owners of such securities.
SIGNATURES
The undersigned certify, after reasonable inquiry and to the best knowledge
and belief of the undersigned, that the information set forth in this
Statement is true, complete and correct. The undersigned agree to the
filing of this single Statement on Schedule 13G.
Advisory Research, Inc.
Date: February 16, 2016 By: /s/ Susan Steiner
Name: Susan Steiner
Title: Chief Compliance Officer
Piper Jaffray Companies
Date: February 16, 2016 By: /s/ Christopher D. Crawshaw
Name: Christopher D. Crawshaw
Title: Head of Asset Management
Exhibit 1
WHEREAS, in accordance with Rule 13d-1(k)(1) under the Securities
and Exchange Act of 1934 (the Act), only one joint Statement and
any amendments thereto need to be filed whenever one or more persons
are required to file such a Statement or any amendments thereto
pursuant to Section 13(d) of the Act with respect to the same
securities,provided that said persons agree in writing that such
Statement or amendments thereto is filed on behalf of each of them;
NOW, THEREFORE, the parties hereto agree as follows:
Advisory Research, Inc. and Piper Jaffray Companies, do hereby
agree, in accordance with Rule 13d-1(k)(1) under the Act, to
file a Statement on Schedule 13G relating to their ownership of
the Common Units representing Limited Partnership Interests in
the Issuer, and do hereby further agree that said Statement on
Schedule 13G shall be filed on behalf of each of them.
Advisory Research, Inc.
Date: February 16, 2016 By: /s/ Susan Steiner
Name: Susan Steiner
Title: Chief Compliance Officer
Piper Jaffray Companies
Date: February 16, 2016 By: /s/ Christopher D. Crawshaw
Name: Christopher D. Crawshaw
Title: Head of Asset Management