Statement of Changes in Beneficial Ownership (4)

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 OF SECURITIES
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* Stratton Marc David	2. Issuer Name and Ticker or Trading Symbol Summit Midstream Partners, LP [ SMLP ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) See remarks below.
(Last) (First) (Middle) C/O SUMMIT MIDSTREAM PARTNERS, LP, 910 LOUISIANA STREET, SUITE 4200	3. Date of Earliest Transaction (MM/DD/YYYY) 3/15/2021
(Street) HOUSTON, TX 77002 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Units	3/15/2021		M		10104	A	⁽¹⁾	10104	D
Common Units	3/15/2021		F		99 ⁽²⁾	D	$29.00	10005	D
Common Units	3/15/2021		F		394 ⁽²⁾	D	$29.00	9611	D
Common Units	3/15/2021		F		2550 ⁽²⁾	D	$29.00	7061	D

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		7. Title and Amount of Securities Underlying Derivative Security (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)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)
Phantom Units	⁽¹⁾	3/15/2021		M			328	⁽³⁾	⁽⁴⁾	Common Units	328	$0.00	0 ⁽⁵⁾	D
Phantom Units	⁽¹⁾	3/15/2021		M			1307	⁽⁶⁾	⁽⁴⁾	Common Units	1307	$0.00	1306 ⁽⁵⁾	D
Phantom Units	⁽¹⁾	3/15/2021		M			8469	⁽⁷⁾	⁽⁴⁾	Common Units	8469	$0.00	16937 ⁽⁵⁾	D

Explanation of Responses:
(1)	Each phantom unit is the economic equivalent of one common unit.
(2)	Common Units being withheld to pay tax liability.
(3)	The final one-third of the phantom units subject to the original award agreement vested on March 15, 2021, on the third anniversary of the March 15, 2018 grant date. The Reporting Person received Distribution Equivalent Rights ("DERs") for each phantom 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 phantom units.
(4)	The phantom units and associated DERs do not expire. The phantom units are settled upon vesting in common units (on a one-for-one basis) or in cash, at the discretion of the Issuer.
(5)	Total excludes phantom units from other tranches with different vesting and expiration dates.
(6)	One-third of the phantom units subject to the original award agreement vested on March 15, 2021, with the final one-third of the phantom units subject to vesting on the third anniversary of the March 15, 2019 grant date, subject to continued employment. The Reporting Person received DERs for each phantom 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 phantom units.
(7)	One-third of the phantom units subject to the original award agreement vested on March 15, 2021, with the remaining phantom units subject to vesting on the second and third anniversaries of the March 15, 2020 reference date, subject to continued employment. The Reporting Person received DERs for each phantom 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 phantom units.

Remarks:
The Reporting Person is Executive Vice President and Chief Financial Officer of Summit Midstream GP, LLC, the general partner of the Issuer (the "General Partner"). The Issuer is managed by the directors and executive officers of the General Partner.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Stratton Marc David C/O SUMMIT MIDSTREAM PARTNERS, LP 910 LOUISIANA STREET, SUITE 4200 HOUSTON, TX 77002			See remarks below.