SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Harrison Matthew S. (Last) (First) (Middle) C/O SUMMIT MIDSTREAM PARTNERS, LP 1790 HUGHES LANDING BLVD., SUITE 500 (Street) THE WOODLANDS TX 77380 (City) (State) (Zip)	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.
	3. Date of Earliest Transaction (Month/Day/Year) 03/15/2018
	4. If Amendment, Date of Original Filed (Month/Day/Year)	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. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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 Units	03/15/2018		M		31,178	A	(1)	67,310	D
Common Units	03/15/2018		F		3,357	D	$15.25	63,953	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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		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: 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
Phantom Units	(1)	03/15/2018		M			6,187	(2)	(3)	Common Units	6,187	$0.00	0	D
Distribution Equivalent Rights	$6.885	03/15/2018		D			6,187	(2)	(3)	Common Units	6,187	$0.00	0	D
Phantom Units	(1)	03/15/2018		M			14,620	(4)	(3)	Common Units	14,620	$0.00	14,619	D
Distribution Equivalent Rights	$4.6	03/15/2018		D			14,620	(4)	(3)	Common Units	14,620	$0.00	0	D
Phantom Units	(1)	03/15/2018		M			10,371	(5)	(3)	Common Units	10,371	$0.00	20,740	D
Distribution Equivalent Rights	$2.3	03/15/2018		D			10,371	(5)	(3)	Common Units	10,371	$0.00	0	D
Phantom Units	(1)	03/15/2018		A		44,262		(6)	(3)	Common Units	44,262	$0.00	44,262	D

Explanation of Responses:

1. Each phantom unit is the economic equivalent of one common unit.

2. The final one-third of the phantom units subject to the original award agreement vested on March 15, 2018, on the third anniversary of the March 15, 2015 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.

3. 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.

4. One-third of the phantom units subject to the original award agreement vested on March 15, 2018, with the final one-third of the phantom units subject to vesting on the third anniversary of the March 15, 2016 grant date, subject to continued employment. 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.

5. One-third of the phantom units subject to the original award agreement vested on March 15, 2018, with the remaining phantom units subject to vesting on the second and third anniversaries of the March 15, 2017 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.

6. One-third of the phantom 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 Grant Date (March 15, 2018), subject to continued employment and accelerated vesting as provided in the applicable award agreement. The Reporting Person will receive distribution equivalent rights 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.

	/s/ Brock M. Degeyter, Attorney-in-Fact for Matthew S. Harrison	03/16/2018
	** Signature of Reporting Person	Date
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