FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.         
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
                                                                                  
OMB APPROVAL
OMB Number: 3235-0287
Estimated average burden
hours per response...
0.5
                      
Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
                      

1. Name and Address of Reporting Person *

SEMPLE FRANK M
2. Issuer Name and Ticker or Trading Symbol

MPLX LP [ MPLX ]
5. Relationship of Reporting Person(s) to Issuer (Check all applicable)

__X__ Director                    _____ 10% Owner
_____ Officer (give title below)    _____ Other (specify below)
(Last)          (First)          (Middle)

C/O MPLX LP, 200 E. HARDIN STREET
3. Date of Earliest Transaction (MM/DD/YYYY)

4/1/2025
(Street)

FINDLAY, OH 45840
4. If Amendment, Date Original Filed (MM/DD/YYYY)

 
6. Individual or Joint/Group Filing (Check Applicable Line)

_X _ Form filed by One Reporting Person
___ 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. Trans. Date 2A. Deemed Execution Date, if any 3. Trans. 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) 4/1/2025  A  220.446 (1)A$0 51,079.232 D  
Common Units (Limited Partner Interests)         333,337 I Frank M Semple Revocable Trust 
Common Units (Limited Partner Interests)         111,180 I Robin Y Semple 2012 Dynasty Trust 
Common Units (Limited Partner Interests)         48,777 I EK Holdings LLC 

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security3. Trans. Date3A. Deemed Execution Date, if any4. Trans. Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
6. Date Exercisable and Expiration Date7. 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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares

Explanation of Responses:
(1) Represents the reporting person's second quarter 2025 equity retainer award prorated for the period beginning April 1, 2025 and ending April 30, 2025. As disclosed in MPLX's annual report of Form 10-K for the year ended December 31, 2024, beginning in May 2025, MPLX's non-management directors will receive an annual equity retainer consisting of one grant in the amount of $125,000, generally made on the day following the annual meeting of shareholders of Marathon Petroleum Corporation (the parent company of MPLX's general partner).

Remarks:
The Reporting Person is a Director of MPLX GP LLC, the general partner of the Issuer. The Issuer is managed by the directors and executive officers of MPLX GP LLC.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director10% OwnerOfficerOther
SEMPLE FRANK M
C/O MPLX LP
200 E. HARDIN STREET
FINDLAY, OH 45840
X



Signatures
/s/ Molly R. Benson, Attorney-in-Fact for Frank M. Semple4/3/2025
**Signature of Reporting PersonDate


Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*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).
Note:File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.