Sec Form 4 Filing - SUMMIT MIDSTREAM PARTNERS HOLDINGS, LLC @ Summit Midstream Partners, LP - 2014-09-09

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person SUMMIT MIDSTREAM PARTNERS HOLDINGS, LLC 2. Issuer Name and Ticker or Trading Symbol Summit Midstream Partners, LP [ SMLP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) SEE REMARKS (Last) (First) (Middle) C/O SUMMIT MIDSTREAM PARTNERS LP, 2100 MCKINNEY AVENUE, SUITE 1250 3. Date of Earliest Transaction (MM/DD/YY) 09/09/2014 (Street) DALLAS, TX75201 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price COMMON UNITS (LIMITED PARTNER INTERESTS) 09/09/2014 S 4,347,826 D $ 52.05 ( 1 ) 5,293,571 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SUMMIT MIDSTREAM PARTNERS HOLDINGS, LLC C/O SUMMIT MIDSTREAM PARTNERS LP 2100 MCKINNEY AVENUE, SUITE 1250 DALLAS, TX75201 X X SEE REMARKS SUMMIT MIDSTREAM PARTNERS, LLC 2100 MCKINNEY AVENUE, SUITE 1250 DALLAS, TX75201 X X SUMMIT MIDSTREAM GP, LLC C/O SUMMIT MIDSTREAM PARTNERS, LLC 2100 MCKINNEY AVENUE, SUITE 1250 DALLAS, TX75201 X ENERGY CAPITAL PARTNERS II, LLC 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS, NJ07078 X X ENERGY CAPITAL PARTNERS II, LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS, NJ07078 X ENERGY CAPITAL PARTNERS II-A, LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS, NJ07078 X ENERGY CAPITAL PARTNERS II-B IP, LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS, NJ07078 X ENERGY CAPITAL PARTNERS II-C (SUMMIT IP), LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS, NJ07078 X Energy Capital Partners II (Summit Co-Invest), LP 51 JOHN F. KENNEDY PARKWAY, SUITE 200 SHORT HILLS, NJ07078 X Signatures /s/ Brock M. Degeyter, Senior Vice President, General Counsel and Secretary, Summit Midstream Partners Holdings, LLC 09/09/2014 Signature of Reporting Person Date /s/ Steven J. Newby, President and Chief Executive Officer, Summit Midstream Partners, LLC 09/09/2014 Signature of Reporting Person Date /s/ Steven J. Newby, President and Chief Executive Officer, Summit Midstream GP, LLC 09/09/2014 Signature of Reporting Person Date Energy Capital Partners II, LP; By: Energy Capital Partners GP II, LP, its General Partner; By: Energy Capital Partners II, LLC, its General Partner; By: /s/ Christopher M. Leininger, Deputy General Counsel 09/09/2014 Signature of Reporting Person Date Energy Capital Partners II-A, LP; By: Energy Capital Partners GP II, LP, its General Partner; By: Energy Capital Partners II, LLC, its General Partner; By: /s/ Christopher M. Leininger, Deputy General Counsel 09/09/2014 Signature of Reporting Person Date Energy Capital Partners II-B IP, LP; By: Energy Capital Partners GP II, LP, its General Partner; By: Energy Capital Partners II, LLC, its General Partner; By: /s/ Christopher M. Leininger, Deputy General Counsel 09/09/2014 Signature of Reporting Person Date Energy Capital Partners II-C (Summit IP), LP; By: Energy Capital Partners GP II, LP, its General Partner; By: Energy Capital Partners II, LLC, its General Partner; By: /s/ Christopher M. Leininger, Deputy General Counsel 09/09/2014 Signature of Reporting Person Date Energy Capital Partners II (Summit Co-Invest), LP; By: Energy Capital Partners GP II Co-Investment (Summit), LLC, its General Partner; By: Energy Capital Partners II, LLC, its Managing Member; By: /s/ Christopher M. Leininger, Deputy General Counsel 09/09/2014 Signature of Reporting Person Date /s/ Christopher M. Leininger, Deputy General Counsel, Energy Capital Partners II, LLC 09/09/2014 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On September 9, 2014, Summit Midstream Partners Holdings, LLC ("SMPH") sold 4,347,826 common units representing limited partner interests in the Issuer ("Common Units").

Remarks: Energy Capital Partners II, LLC ("ECP"), Energy Capital Partners II, LP ("ECP II"), Energy Capital Partners II-A, LP ("ECP II-A"), Energy Capital Partners II-B IP, LP ("ECP II-B"), Energy Capital Partners II-C (Summit IP), LP ("ECP II-C"), Energy Capital Partners II (Summit Co-Invest), LP ("ECP Summit Co-Invest" and together with ECP II, ECP II-A, ECP II-B and ECP II-C, the "ECP Funds"), collectively hold greater than a majority of the membership interest in Summit Midstream Partners, LLC ("Summit ") and are entitled to elect five of the five directors of Summit. Summit is the sole member of SMPH and as such, may be deemed to have indirect beneficial ownership of the common and subordinated units reported herein. Accordingly, ECP and the ECP Funds may be deemed to indirectly beneficially own the common units and subordinated units held by SMPH but disclaim beneficial ownership except to the extent of their pecuniary interest therein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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