Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
COMMON UNITS (LIMITED PARTNER INTERESTS)^F1,F2	Feb 16, 2016	C	24,409,850	—	A	29,703,421	I	BY: SUMMIT MIDSTREAM PARTNERS HOLDINGS, LLC
COMMON UNITS (LIMITED PARTNER INTERESTS)^F4,F5,F6,F3	Feb 16, 2016	P	59,025	$16.18	A	2,299,194	I	BY: SMLP HOLDINGS, LLC
COMMON UNITS (LIMITED PARTNER INTERESTS)^F4,F6,F7,F3	Feb 17, 2016	P	90,978	$16.06	A	2,390,172	I	BY: SMLP HOLDINGS, LLC
COMMON UNITS (LIMITED PARTNER INTERESTS)^F4,F6,F8,F3	Feb 18, 2016	P	60,262	$15.64	A	2,450,434	I	BY: SMLP HOLDINGS, LLC
COMMON UNITS (LIMITED PARTNER INTERESTS)^F2	holding	—	—		—	151,160	I	BY: SUMMIT MIDSTREAM PARTNERS, LLC

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
SUBORDINATED UNITS (LIMITED PARTNER INTERESTS)^F1,F2	$0.00	Feb 16, 2016	C	24,409,850	D	—	—	COMMON UNITS (LIMITED PARTNER INTERESTS)	24,409,850	0	I

Explanation of responses

F1The subordinated units were converted into common units on a one-for-one basis after the expiration of the subordination period, which occurred on February 16, 2016, pursuant to the Issuer's First Amended and Restated Agreement of Limited Partnership.
F2The subordinated units were held by Summit Midstream Partners Holdings, LLC ("SMPH"). The sole member of SMPH is in Summit Midstream Partners, LLC ("Summit"). Energy Capital Partners II, LP and its parallel and co-investment funds (collectively, the "ECP Funds"), hold, in the aggregate, greater than a majority of the membership interests in Summit. Energy Capital Partners II, LLC ("ECP II," and together with the ECP Funds, "ECP") is the general partner of the general partner of each ECP Fund that holds membership interests in Summit and has voting and investment control over the securities held thereby. Accordingly, ECP may be deemed to indirectly beneficially own the 29,703,421 common units now held by SMPH in addition to the 151,160 common units held by Summit, but disclaim beneficial ownership except to the extent of their pecuniary interest therein.
F3Certain of the ECP Funds also collectively hold all of the membership interests in SMLP Holdings, LLC (''SMLP Holdings''). Accordingly, ECP II and certain of the ECP Funds may be deemed to indirectly beneficially own the 2,450,434 common units held by SMLP Holdings but disclaim beneficial ownership except to the extent of their pecuniary interest therein.
F4Units were purchased pursuant to a 10b5-1 plan entered into on December 15, 2015.
F5These common units were purchased in multiple transactions ranging from $15.70 to $16.50, inclusive.
F6The price reported in Column 4 is a weighted average price. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units purchased at each separate price within the ranges set forth in footnotes 5, 7 and 8.
F7These common units were purchased in multiple transactions ranging from $15.77 to $16.41, inclusive.
F8These common units were purchased in multiple transactions ranging from $15.28 to $16.05, inclusive.