X0306 4 2021-03-15 0 0001549922 Summit Midstream Partners, LP SMLP 0001774293 Jacobe James Lee C/O SUMMIT MIDSTREAM PARTNERS, LP 910 LOUISIANA STREET, SUITE 4200 HOUSTON TX 77002 1 0 0 1 See Remarks. Common Units (Limited Partner Interests) 2021-03-15 4 A 0 6667 0.00 A 19516 D On November 9, 2020, the Issuer effected a 1-for-15 reverse stock split (the "Reverse Unit Split"). Pursuant to the Reverse Unit Split, common unitholders received one common unit for every 15 common units owned at the close of business on November 9, 2020. All fractional units created by the Reverse Unit Split were rounded to the nearest whole unit. The common units began trading on a split-adjusted basis on November 10, 2020. After giving effect to the Reverse Unit Split, the number of issued and outstanding common units decreased to 3,774,992. The Reporting Person is a director of Summit Midstream GP, LLC, the general partner of the Issuer (the "General Partner"). The Issuer is managed by the directors and executive officers of the General Partner. Exhibit List Exhibit 24.1 - Power of Attorney /s/ James D. Johnston, Attorney-in-Fact for James Lee Jacobe 2021-03-15