Ownership Submission
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 OF SECURITIES

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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(Print or Type Responses)
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 (Month/Day/Year)
02/01/2018
(Street)

FINDLAY, OH 45840
4. If Amendment, Date 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
(City)
(State)
(Zip)
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) 02/01/2018   A   386,611,111 (1) (2) (3) A (2) (3) 504,701,934 I See Footnotes (1) (2) (3)

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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 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, OH 45840
  X   X    
MPC Investment LLC
539 S. MAIN STREET
FINDLAY, OH 45840
  X   X    
MPLX GP LLC
200 E. HARDIN STREET
FINDLAY, OH 45840
  X   X    
MPLX Logistics Holdings LLC
200 E. HARDIN STREET
FINDLAY, OH 45840
  X   X    
MPLX Holdings Inc.
539 S. MAIN ST.
FINDLAY, OH 45840
  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:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(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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