MPLX (MPLX) Form 4 MPLX / HYDROCARBON L.L.C. MARKWEST ownership change

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

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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)
09/01/2016

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)	09/01/2016		D(1)		21,401,137(1)(2)(3)(4)	D	(1)	58,064,999	I	See Footnotes(1)(2)(3)(4)
Common Units (Limited Partner Interests)	09/02/2016		A(5)		28,554,314(2)(3)(4)(5)	A	(5)	86,619,313	I	See Footnotes(2)(3)(4)(5)

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)

1. Name and Address of Reporting Person^*

MARKWEST HYDROCARBON L.L.C.

(Last) (First) (Middle)

1515 ARAPAHOE STREET

TOWER 1, SUITE 1600

(Street)

DENVER CO 80202

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

MPC Investment LLC

(Last) (First) (Middle)

539 S. MAIN STREET

(Street)

FINDLAY OH 45840

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

MPLX Holdings Inc.

(Last) (First) (Middle)

539 S. MAIN ST.

(Street)

FINDLAY OH 45840

(City) (State) (Zip)

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)

1. Name and Address of Reporting Person^*

MPLX GP LLC

(Last) (First) (Middle)

200 E. HARDIN STREET

(Street)

FINDLAY OH 45840

(City) (State) (Zip)

Explanation of Responses:

1. Pursuant to a Master Reorganization Agreement effective September 1, 2016 by and among MPLX Holdings Inc. ("Holdings"), MarkWest Energy Partners, L.P. ("MarkWest"), MWE GP LLC ("MWE GP"), MPLX LP ("MPLX"), MPLX GP LLC ("the "General Partner"), MPC Investment LLC ("MPC Investment"), MPLX Logistics Holdings LLC ("Logistics Holdings") and MarkWest Hydrocarbon, L.L.C. ("Hydrocarbon"), MPLX transferred 980 shares of Holdings common stock to Logistics Holdings in exchange for 21,401,137 common units held by Logistics Holdings.

2. This Form 4 is filed jointly by Marathon Petroleum Corporation ("MPC"), MPC Investment, the General Partner, Logistics Holdings, Holdings and Hydrocarbon. MPC Investment, a direct wholly-owned subsidiary of MPC, owns all of the membership interests or stock in the General Partner, Logistics Holdings and Holdings. Holdings owned all of the membership interests in Hydrocarbon as of September 2, 2016. Accordingly, the General Partner, Logistics Holdings and Holdings are all indirect wholly-owned subsidiaries of MPC, and Hydrocarbon was an indirect wholly-owned subsidiary of MPC as of September 2, 2016.

3. The General Partner directly owns 7,193,467 general partner units, representing a 2% general partner interest in the Issuer. MPC Investment owns all of the membership interests or stock in the General Partner, Logistics Holdings and Holdings and MPC owns all of the membership interests in MPC Investment. Holdings owned all of the membership interests in Hydrocarbon as of September 2, 2016. Accordingly, MPC and MPC Investment both may be deemed to have indirectly beneficially owned the securities of the Issuer directly held by the General Partner, Logistics Holdings, Holdings and Hydrocarbon but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein.

4. The General Partner directly owns 7,193,467 general partner units, representing its 2% general partner interest in the Issuer.

5. Pursuant to a Master Reorganization Agreement effective September 1, 2016 by and among Holdings, MarkWest, MWE GP, MPLX, the General Partner, MPC Investment, Logistics Holdings and Hydrocarbon, all issued and outstanding Class A Units representing limited partner interests of MPLX were exchanged for newly created and issued common units representing limited partner interests of MPLX on a one-to-one conversion, eliminating all issued and outstanding Class A Units representing limited partner interests of MPLX.

Remarks:

	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, Marathon Petroleum Corporation	09/06/2016
	/s/ Director and Secretary of the Member of MarkWest Hydrocarbon, L.L.C., MPLX Holdings Inc.	09/06/2016
	/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPC Investment LLC	09/06/2016
	/s/ Molly R. Benson, Director and Secretary, MPLX Holdings Inc.	09/06/2016
	/s/ Molly R. Benson, Assistant Secretary, MPLX Logistics Holdings LLC	09/06/2016
	/s/ Molly R. Benson, Vice President and Corporate Secretary, MPLX GP LLC	09/06/2016
	** Signature of Reporting Person	Date
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