Summit Midstream Corporation

Item 1.01. Entry into a Material Definitive Agreement. On March 31, 2026, Summit Midstream Corporation, a Delaware corporation (the “Company”), entered into a Securities Purchase Agreement (the “Purchase Agreement”), by and among the Company, Summit Midstream Partners, LP, a Delaware limited partnership (the “Partnership”), and Tall Oak Midstream Holdings, LLC, a Delaware limited liability company (the “Tall Oak Midstream Holdings”), and solely for purposes of modifying certain existing registration rights as detailed in the Purchase Agreement, Connect Midstream, LLC, a Delaware limited liability company (“Connect Midstream”), pursuant to which the Company agreed to issue and sell to Tall Oak Midstream Holdings (or its designated members) 1,351,351 shares (the “Shares”) of common stock of the Company (“Common Stock”) in exchange for $42,000,000 in cash. The Purchase Agreement contained customary representations, warranties, covenants, conditions to closing, and termination provisions. The closing of the transactions (the “Closing”) contemplated by the Purchase Agreement (the “Transactions”) occurred on March 31, 2026. A total of 1,351,351 shares of Common Stock were issued at the Closing pursuant to the Purchase Agreement. The Shares were issued at a price of $31.08 per share, which represents the “Minimum Price” in accordance with New York Stock Exchange regulations. The Shares are subject to a 6-month lock up period and other terms and conditions. The Purchase Agreement and the Transactions were unanimously approved by the Audit Committee of the Board of Directors of the Company, which is comprised solely of independent and disinterested directors. The Purchase Agreement amends and modifies the Investor and Registration Rights Agreement, dated December 2, 2024 (the “IRRA”), by and among the Company, Tall Oak Midstream Holdings, Connect Midstream and Tall Oak Midstream Investments, LLC, a Delaware limited liability company, such that the Shares issued to Tall Oak Midstream Holdings (or its designated members) constitute “Registerable Securities” under the IRRA, and, pursuant to the terms of the Purchase Agreement and the IRRA, the Company will use commercially reasonable efforts to prepare and file a Registration Statement (as defined in the IRRA) with the SEC (or amend by post-effective amendment a previously filed Registration Statement, covering the resale of all of the Shares for an offering to be made on a continuous basis pursuant to Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”), within 90 days of the Closing. Tall Oak Midstream Holdings and Connect Midstream are affiliates of Tailwater Capital LLC (“Tailwater”). As of the date of the Purchase Agreement and prior to the Closing, affiliates of Tailwater beneficially owned approximately 35% of the outstanding voting power of the Company. Four of the directors on the Board of Directors of the Company are affiliates of Tailwater. Following the transactions, Tailwater and its affiliated entities beneficially own approximately 39% of Summit's outstanding equity. The foregoing descriptions of the Purchase Agreement and the IRRA do not purport to be complete and are subject to, and qualified in their entirety, as applicable, by, (i) the full text of the Purchase Agreement, which is filed as Exhibit 10.1 to this Current Report on Form 8-K, and (ii) the full text of the IRRA, which is incorporated in this Current Report on Form 8-K by reference to Exhibit 10.2 filed with the Company’s Current Report on Form 8-K filed with the SEC on December 3, 2024.

Item 3.02. Unregistered Sales of Equity Securities. The disclosure set forth in Item 1.01 above is incorporated into this Item 3.02 by reference. The Shares were issued in reliance on the exemption from registration requirements under the Securities Act, pursuant to Section 4(a)(2) thereof.

Item 7.01. Regulation FD Disclosure. On March 31, 2026, the Company issued a press release announcing the signing of the Purchase Agreement. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference. The information in this Item 7.01, including Exhibit 99.1, is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of Section 18, and shall not be incorporated by reference in any filing under the Securities Act or the Exchange Act, except as set forth by specific reference in such filing.