X0306 4 2020-05-28 1 0001549922 Summit Midstream Partners, LP SMLP 0001558915 ENERGY CAPITAL PARTNERS II, LLC 40 BEECHWOOD ROAD SUMMIT NJ 07901 0 0 1 0 0001456360 ENERGY CAPITAL PARTNERS II, LP 40 BEECHWOOD ROAD SUMMIT NJ 07901 0 0 1 0 0001456364 ENERGY CAPITAL PARTNERS II-A, LP 40 BEECHWOOD ROAD SUMMIT NJ 07901 0 0 1 0 0001558920 ENERGY CAPITAL PARTNERS II-B IP, LP 40 BEECHWOOD ROAD SUMMIT NJ 07901 0 0 1 0 0001558930 ENERGY CAPITAL PARTNERS II-C (SUMMIT IP), LP 40 BEECHWOOD ROAD SUMMIT NJ 07901 0 0 1 0 0001532708 Energy Capital Partners II (Summit Co-Invest), LP 40 BEECHWOOD ROAD SUMMIT NJ 07901 0 0 1 0 Common Units (Limited Partner Interests) 2020-05-28 4 D 0 5915827 D 0 I By SMLP Holdings, LLC Common Units (Limited Partner Interests) 2020-05-28 4 D 0 45318866 D 0 I By Summit Midstream Partners, LLC On May 28, 2020, pursuant to a purchase agreement, dated as of May 3, 2020, the Issuer purchased (i) all the outstanding limited liability company interests of Summit Midstream Partners, LLC ("Summit Investments"), which is the sole member of Summit Midstream Partners Holdings, LLC ("SMP Holdings"), which in turn owns 45,318,866 common units representing limited partner interests in the Issuer (the "Common Units"), and (ii) 5,915,827 Common Units held by SMLP Holdings, LLC ("SMLP") for a total purchase price of $35 million in cash and warrants to purchase up to 10 million Common Units. As a result of these transactions, Summit Investments became a wholly owned subsidiary of the Issuer. Summit Investments is the sole member of SMP Holdings. Energy Capital Partners II, LLC ("ECP") indirectly controls 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"), and 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"). Prior to the transactions reported herein, the ECP Funds owned a majority of the membership interests in Summit Investments and therefore may have been deemed to indirectly beneficially own the Common Units held of record by SMP Holdings. The ECP Funds, other than ECP Summit Co-Invest, hold all of the membership interests in SMLP. Accordingly, each of them, other than ECP Summit Co-Invest, may have been deemed to share beneficially ownership of the Common Units held by SMLP. Energy Capital Partners II, LLC, By: /s/ Christopher M. Leininger, Partner and General Counsel 2021-10-22 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, Partner and General Counsel 2021-10-22 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: Christopher M. Leininger, Partner and General Counsel 2021-10-22 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, Partner and General Counsel 2021-10-22 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, Partner and General Counsel 2021-10-22 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, Partner and General Counsel 2021-10-22