UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 x For the fiscal year ended December 31, 2023 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 o For the transition period from to Commission file number: 001-35666 Summit Midstream Partners, LP (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporati ...