Sec Form 4 Filing - Johnston James David @ Summit Midstream Corp - 2025-03-14

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 Johnston James David 2. Issuer Name and Ticker or Trading Symbol Summit Midstream Corp [ SMC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Executive VP, GC, CCO and Secy (Last) (First) (Middle) C/O SUMMIT MIDSTREAM CORPORATION, 910 LOUISIANA STREET, SUITE 4200 3. Date of Earliest Transaction (MM/DD/YY) 03/14/2025 (Street) HOUSTON, TX77002 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 03/15/2025 M 5,544 A 41,729 D Common Stock 03/15/2025 F 1,350 ( 2 ) D $ 37.44 40,379 D Common Stock 03/15/2025 M 4,018 A 44,397 D Common Stock 03/15/2025 F 979 ( 2 ) D $ 37.44 43,418 D Common Stock 03/15/2025 M 9,793 A 53,211 D Common Stock 03/15/2025 F 3,395 ( 2 ) D $ 37.44 49,816 D

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 Corporation Restricted Stock Units ( 1 ) 03/14/2025 A 13,958 ( 3 ) ( 4 ) Common Stock 13,958 $ 0 105,908 D Corporation Restricted Stock Units ( 1 ) 03/14/2025 A 13,958 ( 5 ) ( 4 ) Common Stock 13,958 $ 0 119,866 D Corporation Restricted Stock Units ( 1 ) 03/15/2025 M 5,544 ( 6 ) ( 4 ) Common Stock 5,544 $ 0 114,322 D Corporation Restricted Stock Units ( 1 ) 03/15/2025 M 4,018 ( 7 ) ( 4 ) Common Stock 4,018 $ 0 110,304 D Corporation Restricted Stock Units ( 1 ) 03/15/2025 M 9,793 ( 8 ) ( 4 ) Common Stock 9,793 $ 0 100,511 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Johnston James David C/O SUMMIT MIDSTREAM CORPORATION 910 LOUISIANA STREET, SUITE 4200 HOUSTON, TX77002 Executive VP, GC, CCO and Secy Signatures /s/ James David Johnston 03/18/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each corporation restricted stock unit is the economic equivalent of one common stock. ( 2 )Common stocks being withheld to pay tax liability. ( 3 )One-third of the corporation restricted stock units (rounded down to the nearest whole number of units, except in the case of the final vesting date) shall vest on each of the first, second and third anniversaries of the March 14, 2025, reference date, subject to continued employment and accelerated vesting as provided in the applicable award agreement. The Reporting Person will receive distribution equivalent rights ("DERs") for each corporation restricted stock unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the corporation restricted stock units. ( 4 )The corporation restricted stock units and associated DERs do not expire. The corporation restricted stock units are settled upon vesting in common stocks (on a one-for-one basis) or in cash, at the discretion of the Issuer. ( 5 )The corporation restricted stock units shall vest if and to the extent that the corporation restricted stock units are earned during the performance period from January 1, 2025 through December 31, 2027, which will depend on whether the performance criteria are achieved as determined by the committee as soon as reasonably practicable, but no later than sixty (60) days following December 31, 2027, the last day of the Performance Period. The vesting of the corporation restricted stock units is subject to continued employment and accelerated vesting as provided in the applicable award agreement. The Reporting Person will receive DERs for each corporation restricted stock unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the corporation restricted stock units. ( 6 )The final one-third of the corporation restricted stock units subject to the original award agreement vested on March 15, 2025, the third anniversary of the March 15, 2022, reference date. The Reporting Person received DERs for each corporation restricted stock unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the corporation restricted stock units. ( 7 )The final twenty percent of the corporation restricted stock units subject to the original award agreement vested on March 15, 2025, the third anniversary of the March 15, 2022, reference date. The Reporting Person received DERs for each corporation restricted stock unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the corporation restricted stock units. ( 8 )One-third of the corporation restricted stock units subject to the original award agreement vested on March 15, 2025, and the final one-third of the corporation restricted stock units shall vest on the third anniversary of the March 15, 2023, reference date, subject to continued employment. The Reporting Person received DERs for each corporation restricted stock unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the corporation restricted stock units.

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.