SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 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, LLC (Last) (First) (Middle) 2100 MCKINNEY AVENUE, SUITE 1250 (Street) DALLAS TX 75201 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 09/27/2012	3. Issuer Name and Ticker or Trading Symbol Summit Midstream Partners, LP [ SMLP ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Units (Limited Partner Interests)	11,904,850(4)(5)	D(1)(2)(3)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Subordinated Units (Limited Partner Interests)	(6)	(6)	Common Units	24,409,850(4)	0	D(1)(2)(3)

1. Name and Address of Reporting Person* SUMMIT MIDSTREAM PARTNERS, LLC (Last) (First) (Middle) 2100 MCKINNEY AVENUE, SUITE 1250 (Street) DALLAS TX 75201 (City) (State) (Zip)

1. Name and Address of Reporting Person* SUMMIT MIDSTREAM GP, LLC (Last) (First) (Middle) C/O SUMMIT MIDSTREAM PARTNERS, LLC 2100 MCKINNEY AVENUE, SUITE 1250 (Street) DALLAS TX 75201 (City) (State) (Zip)

1. Name and Address of Reporting Person* ENERGY CAPITAL PARTNERS II, LLC (Last) (First) (Middle) 51 JOHN F. KENNEDY PARKWAY, SUITE 200 (Street) SHORT HILLS NJ 07078 (City) (State) (Zip)

1. Name and Address of Reporting Person* ENERGY CAPITAL PARTNERS II, LP (Last) (First) (Middle) 51 JOHN F. KENNEDY PARKWAY, SUITE 200 (Street) SHORT HILLS NJ 07078 (City) (State) (Zip)

1. Name and Address of Reporting Person* ENERGY CAPITAL PARTNERS II-A, LP (Last) (First) (Middle) 51 JOHN F. KENNEDY PARKWAY, SUITE 200 (Street) SHORT HILLS NJ 07078 (City) (State) (Zip)

1. Name and Address of Reporting Person* ENERGY CAPITAL PARTNERS II-B IP, LP (Last) (First) (Middle) 51 JOHN F. KENNEDY PARKWAY, SUITE 200 (Street) SHORT HILLS NJ 07078 (City) (State) (Zip)

1. Name and Address of Reporting Person* ENERGY CAPITAL PARTNERS II-C (SUMMIT IP), LP (Last) (First) (Middle) 51 JOHN F. KENNEDY PARKWAY, SUITE 200 (Street) SHORT HILLS NJ 07078 (City) (State) (Zip)

1. Name and Address of Reporting Person* Energy Capital Partners II (Summit Co-Invest), LP (Last) (First) (Middle) 51 JOHN F. KENNEDY PARKWAY, SUITE 200 (Street) SHORT HILLS NJ 07078 (City) (State) (Zip)

Explanation of Responses:

1. This Form 3 is filed jointly by Summit Midstream Partners, LLC ("Summit Investments"), Summit Midstream GP, LLC (the "General Partner"), 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") in connection with the effectiveness of the Issuer's Registration Statement on Form S-1 (Registration No. 333-183466) (the "Registration Statement"). ECP is the general partner of the general partner of each of the ECP Funds and has voting and investment control over the securities held thereby.

2. As of the effectiveness of the Registration Statement, Summit Investments owns a 98% limited partnership interest in the Issuer. The General Partner owns a 2% general partnership interest in the Issuer and Summit Investments owns all of the membership interests in the General Partner. Accordingly, Summit Investments may be deemed to indirectly beneficially own the securities of the Issuer held by the General Partner, but disclaims beneficial ownership except to the extent of its pecuniary interest therein.

3. ECP and the ECP Funds collectively hold 88.75% of the membership interest in Summit Investments and are entitled to elect four of the five directors of Summit Investments. Accordingly, ECP and the ECP Funds may be deemed to indirectly beneficially own the common units and subordinated units held by Summit Investments but disclaim beneficial ownership except to the extent of their pecuniary interest therein.

4. As described in the Registration Statement, in connection with the closing of the initial public offering of the Issuer, Summit Investments contributes certain assets to the Issuer and receives (i) 11,904,850 common units, representing a 23.9% limited partner interest in Issuer and (ii) 24,409,850 subordinated units, representing a 49.0% limited partner interest in Issuer (or 10,029,850 common units and 24,409,850 subordinated units, representing a combined 69.1% limited partner interest in the Issuer, if the underwriters exercise their option to purchase additional common units in full). The Issuer also redeems for nominal consideration the current 98% limited partner interest in the Issuer held by Summit Investments.

5. In connection with the closing of the initial public offering of the Issuer, the General Partner will own approximately 996,320 general partner units, representing its 2.0% general partner interest in the Issuer.

6. Each subordinated unit will convert into one common unit at the end of the subordination period described in the Registration Statement.

	/s/ Steven J. Newby, President and Chief Executive Officer, Summit Midstream Partners, LLC	09/27/2012
	/s/ Steven J. Newby, President and Chief Executive Officer, Summit Midstream GP, LLC	09/27/2012
	/s/ Christopher M. Leininger, Deputy General Counsel, Energy Capital Partners II, LLC	09/27/2012
	.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	09/27/2012
	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	09/27/2012
	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	09/27/2012
	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	09/27/2012
	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	09/27/2012
	** Signature of Reporting Person	Date
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