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) 03/01/2017
	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)	03/01/2017		A		12,960,376(1)(2)(3)	A	(3)	99,579,689	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 ("MPC Investment"), MPLX GP LLC (the "General Partner"), MPLX Logistics Holdings LLC ("MPLX Logistics") and MPLX Holdings Inc. ("MPLX Holdings"). MPC Investment, a direct wholly-owned subsidiary of MPC, owns all of the membership interests in both the General Partner and MPLX Logistics and all of the shares of stock of MPLX Holdings. Accordingly, the General Partner, MPLX Logistics and MPLX Holdings are indirect wholly-owned subsidiaries of MPC.

2. The General Partner directly owns 7,636,916 general partner units, representing its 2% general partner interest in the Issuer. MPC Investment owns all of the membership interest in the General Partner and MPC owns all of the membership interest in MPC Investment. Accordingly, MPC and MPC Investment both may be deemed to indirectly beneficially own the securities of the Issuer directly held by the General Partner, but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein.

3. Pursuant to the Membership Interests Contributions Agreement among the Issuer, MPLX Logistics, MPLX Holdings, the General Partner and MPC Investment, on March 1, 2017, MPC Investment agreed to contribute the outstanding membership interests in Hardin Street Transportation LLC, Woodhaven Cavern LLC and MPLX Terminals LLC through a series of intercompany contributions to the Issuer for approximately $1.511 billion in cash and equity consideration valued at approximately $504 million, consisting of: (i) 9,197,900 common units issued to the General Partner, (ii) 2,630,427 common units issued to MPLX Logistics, (iii) 1,132,049 common units issued to MPLX Holdings and (iv) 264,497 general partner units issued to the General Partner. The common units and general partner units issued were calculated by dividing $503,750,000 by $38.0911, the simple average of the volume weighted average price of a common unit for the 10 trading days ending February 28, 2017.

Remarks:

	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, Marathon Petroleum Corporation	03/03/2017
	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPC Investment LLC	03/03/2017
	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPLX GP LLC	03/03/2017
	/s/ Molly R. Benson, Assistant Secretary, MPLX Logistics Holdings LLC	03/03/2017
	/s/ Molly R. Benson, Director and Secretary, MPLX Holdings Inc.	03/03/2017
	** Signature of Reporting Person	Date
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