Sec Form 4 Filing - Marathon Petroleum Corp @ MPLX LP - 2018-02-01

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 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Marathon Petroleum Corp 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) (Last) (First) (Middle) 539 S. MAIN STREET 3. Date of Earliest Transaction (MM/DD/YY) 02/01/2018 (Street) FINDLAY, OH45840 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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) 02/01/2018 A 386,611,111 ( 1 ) ( 2 ) ( 3 ) A 504,701,934 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Marathon Petroleum Corp 539 S. MAIN STREET FINDLAY, OH45840 X X MPC Investment LLC 539 S. MAIN STREET FINDLAY, OH45840 X X MPLX GP LLC 200 E. HARDIN STREET FINDLAY, OH45840 X X MPLX Logistics Holdings LLC 200 E. HARDIN STREET FINDLAY, OH45840 X X MPLX Holdings Inc. 539 S. MAIN ST. FINDLAY, OH45840 X Signatures /s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, Marathon Petroleum Corporation 02/05/2018 Signature of Reporting Person Date /s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPC Investment LLC 02/05/2018 Signature of Reporting Person Date /s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPLX GP LLC 02/05/2018 Signature of Reporting Person Date /s/ Molly R. Benson, Assistant Secretary, MPLX Logistics Holdings LLC 02/05/2018 Signature of Reporting Person Date /s/ Molly R. Benson, Director and Secretary, MPLX Holdings Inc. 02/05/2018 Signature of Reporting Person Date

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 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 Contribution Agreement dated November 13, 2017 among the Issuer, Logistics, Holdings, the GP and MPCI, on 2/1/2018, MPCI contributed: the membership interests in MPLX Refining Logistics LLC, which owns all of the membership interests in each of Canton Refining Logistics LLC, Catlettsburg Refining Logistics LLC, Detroit Refining Logistics LLC, Galveston Bay Refining Logistics LLC, Garyville Refining Logistics LLC and Robinson Refining Logistics LLC; and all of the membership interests in MPLX Fuels Distribution LLC, to the Issuer for $4.1 billion in cash consideration and equity consideration, consisting of (i) 85,610,278 common units issued to the GP, (ii) 18,176,666 common units issued to Logistics, (iii) 7,824,167 common units issued to Holdings and (iv) 2,277,778 general partner units issued to the GP. ( 3 )Pursuant to the Partnership Interests Restructuring Agreement dated December 15, 2017, between the Issuer and the GP, on 2/1/2018, the GP converted its 10,586,691 general partner units, representing its 2% general partner interest in the Issuer, into a non-economic general partner interest in the Issuer and the GP's general partner units and incentive distribution rights were cancelled and redeemed, in exchange for 275,000,000 newly issued common units issued to the GP.

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