Summit Midstream Corp — Director's Dealing 2026

Mar 18, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Summit Midstream Corp (SMC)
CIK: 0002024218
Period of Report: 2026-03-13

Reporting Person: Johnston James David (Executive VP, GC, CCO and Secy)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-03-13	Common Stock	M	18977	—	Acquired	76664	Direct
2026-03-13	Common Stock	F	7468	$30.29	Disposed	69196	Direct
2026-03-13	Common Stock	M	4653	—	Acquired	73849	Direct
2026-03-13	Common Stock	F	1831	$30.29	Disposed	72018	Direct
2026-03-13	Common Stock	M	9793	—	Acquired	81811	Direct
2026-03-13	Common Stock	F	3854	$30.29	Disposed	77957	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-03-13	Corporation Restricted Stock Units	$	M	18977	Disposed		Common Stock (18977)	Direct
2026-03-13	Corporation Restricted Stock Units	$	M	4653	Disposed		Common Stock (4653)	Direct
2026-03-13	Corporation Restricted Stock Units	$	M	9793	Disposed		Common Stock (9793)	Direct
2026-03-16	Corporation Restricted Stock Units	$	A	17544	Acquired		Common Stock (17544)	Direct
2026-03-16	Corporation Restricted Stock Units	$	A	17544	Acquired		Common Stock (17544)	Direct

Footnotes

F1: Each corporation restricted stock unit is the economic equivalent of one common stock.

F2: Common stocks being withheld to pay tax liability.

F3: The corporation restricted stock units subject to the original award agreement vested on March 13, 2026. The Reporting Person received 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.

F4: 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.

F5: 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) vested on March 13, 2026, with the remaining corporation restricted stock units vesting on the 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 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.

F6: The final one-third of the corporation restricted stock units subject to the original award agreement vested on March 13, 2026. 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.

F7: 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 16, 2026, reference date, 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.

F8: 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, 2026 through December 31, 2028, 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, 2028, 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.

F9: This total includes corporation restricted stock units from other tranches with different vesting dates. On March 16, 2026, when the original award agreement vested, it was certified at an achievement level of 96.7% of the target number of corporation restricted stock units. The remaining 3.3% of the target corporation restricted stock units that were not earned based on the certified performance level were forfeited. The difference between the number of outstanding awards reflected in the Reporting Person's brokerage account and the number previously reported is attributable to this certification and the corresponding forfeiture of the unearned portion of the original award.