Sec Form 4 Filing - Connect Midstream, LLC @ Summit Midstream Corp - 2025-08-26

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Connect Midstream, LLC 2. Issuer Name and Ticker or Trading Symbol Summit Midstream Corp [ SMC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 2021 MCKINNEY AVE,, SUITE 1250 3. Date of Earliest Transaction (MM/DD/YY) 08/26/2025 (Street) DALLAS, TX75021 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.01 08/26/2025 P 72,759 A $ 20.46 ( 1 ) 72,759 ( 1 ) D ( 3 ) Common Stock, par value $0.01 08/27/2025 P 47,401 A $ 20.5 ( 2 ) 120,160 ( 2 ) D ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Connect Midstream, LLC 2021 MCKINNEY AVE, SUITE 1250 DALLAS, TX75021 X Tailwater Energy Fund III LP 2021 MCKINNEY AVE, SUITE 1250 DALLAS, TX75201 X Tailwater Capital LLC 2021 MCKINNEY AVE, SUITE 1250 DALLAS, TX75201 X Downie Jason H 2021 MCKINNEY AVE, SUITE 1250 DALLAS, TX75201 X X Herring Edward 2021 MCKINNEY AVE, SUITE 1250 DALLAS, TX75201 X X Signatures Connect Midstream, LLC, By: /s/ Jason H. Downie, Director 08/28/2025 Signature of Reporting Person Date Tailwater Energy Fund III LP, By: TW GP EF-III LP, its general partner, By: TW GP EF-III GP, LLC, its general partner, By: Tailwater Capital LLC, its sole member, By: /s/ Jason H. Downie, Managing Partner 08/28/2025 Signature of Reporting Person Date Tailwater Capital, LLC, By: /s/ Jason H. Downie, Managing Partner 08/28/2025 Signature of Reporting Person Date /s/ Jason H. Downie 08/28/2025 Signature of Reporting Person Date /s/ Edward Herring 08/28/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $19.87 to $20.75. The Reporting Person undertakes to provide to Summit Midstream Corp (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 shares purchased at each separate price within the ranges set forth in this footnote. ( 2 )The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $20.35 to $20.82. The Reporting Person undertakes 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 shares purchased at each separate price within the ranges set forth in this footnote. ( 3 )The reported securities are held directly by Connect Midstream, LLC. Tailwater Energy Fund III LP is the sole member of Connect Midstream, LLC. TW GP EF-III LP is the general partner of Tailwater Energy Fund III LP. TW GP EF-III GP, LLC is the general partner of TW GP EF-III LP. Tailwater Capital LLC is the sole member of TW GP EF-III GP, LLC. Jason Downie and Edward Herring are each a Managing Partner of Tailwater Capital LLC. Each of the foregoing disclaim beneficial ownership of the reported securities directly held by Connect Midstream, LLC except to the extent of their respective pecuniary interest therein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.