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* Marathon Petroleum Corp (Last) (First) (Middle) 539 S. MAIN STREET (Street) FINDLAY OH 45840 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol MPLX LP [ MPLX ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 09/01/2017
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X 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 (Limited Partner Interests)	09/01/2017		A		18,511,134(1)(2)(3)	A	(2)	118,090,823	I	See Footnotes(1)(2)(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 (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

1. Name and Address of Reporting Person* Marathon Petroleum Corp (Last) (First) (Middle) 539 S. MAIN STREET (Street) FINDLAY OH 45840 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MPC Investment LLC (Last) (First) (Middle) 539 S. MAIN STREET (Street) FINDLAY OH 45840 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MPLX GP LLC (Last) (First) (Middle) 200 E. HARDIN STREET (Street) FINDLAY OH 45840 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MPLX Logistics Holdings LLC (Last) (First) (Middle) 200 E. HARDIN STREET (Street) FINDLAY OH 45840 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MPLX Holdings Inc. (Last) (First) (Middle) 539 S. MAIN ST. (Street) FINDLAY OH 45840 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. This Form 4 is filed jointly by Marathon Petroleum Corporation ("MPC"), MPC Investment LLC ("MPCI"), MPLX GP LLC (the "GP"), MPLX Logistics Holdings LLC ("Logistics") and MPLX Holdings Inc. ("Holdings"). MPCI, a direct wholly-owned subsidiary of MPC, owns all of the membership interests in both the GP and Logistics and all of the shares of stock of Holdings. Accordingly, the GP, Logistics and Holdings are all indirect wholly-owned subsidiaries of MPC.

2. Pursuant to the Membership Interests and Shares Contributions Agreement among the Issuer, Logistics, Holdings, the GP and MPCI, on 9/1/2017, MPCI agreed to contribute: the membership interests of Lincoln Pipeline LLC, which holds a 35% interest in Illinois Extension Pipeline Company, L.L.C.; the membership interests of MPL Louisiana Holdings LLC, which holds a 40.7% interest in LOOP LLC; a 58.52% interest in LOCAP LLC; and a 24.51% interest in Explorer Pipeline Company, to the Issuer for $420 million in cash and equity consideration valued at $630 million, consisting of: (i) 13,719,017 common units issued to the GP, (ii) 3,350,893 common units issued to Logistics, (iii) 1,441,224 common units issued to Holdings and (iv) 377,778 general partner units issued to the GP. The units issued were calculated by dividing $630 million by $33.3529, the simple average of the 10 day trading volume weighted average price of a common unit for the 10 trading days ending 8/31/2017.

3. The GP directly owns 8,306,911 general partner units, representing its 2% general partner interest in the Issuer. MPCI owns all of the membership interest in the GP and MPC owns all of the membership interest in MPCI. Accordingly, MPC and MPCI both may be deemed to indirectly beneficially own the securities of the Issuer directly held by the GP, but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein.

Remarks:

	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, Marathon Petroleum Corporation	09/05/2017
	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPC Investment LLC	09/05/2017
	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPLX GP LLC	09/05/2017
	/s/ Molly R. Benson, Assistant Secretary, MPLX Logistics Holdings LLC	09/05/2017
	/s/ Molly R. Benson, Director and Secretary, MPLX Holdings Inc.	09/05/2017
	** Signature of Reporting Person	Date
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