[Form 4] MPLX LP Insider Trading Activity

Rhea-AI Filing Summary

MPLX LP (MPLX) director Frank M. Semple reported acquiring 1,132.302 common units on 11/14/2025, according to a Form 4 insider filing. The units were acquired at a reported price of $0, indicating an award or similar non-cash grant rather than an open-market purchase. Following this transaction, Semple directly holds 57,100.516 MPLX common units. He also reports additional indirect holdings of 333,337 units through the Frank M Semple Revocable Trust, 111,180 units through the Robin Y Semple 2012 Dynasty Trust, and 48,777 units through EK Holdings LLC. Semple serves as a director of MPLX GP LLC, the general partner that manages MPLX LP.

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
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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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

SEMPLE FRANK M

(Last) (First) (Middle)

C/O MPLX LP

200 E. HARDIN 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		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
11/14/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

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

X	Form filed by One Reporting Person
	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)	11/14/2025		A		1,132.302	A	$0	57,100.516	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 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

Explanation of Responses:

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.

	/s/ Molly R. Benson, Attorney-in-Fact for Frank M. Semple	11/18/2025
	** Signature of Reporting Person	Date
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 Number.

FAQ

What insider transaction did MPLX (MPLX) report for Frank M. Semple?

Frank M. Semple reported acquiring 1,132.302 MPLX LP common units (limited partner interests) on 11/14/2025, as disclosed in a Form 4 filing.

At what price were the MPLX units acquired by director Frank M. Semple?

The filing reports that the 1,132.302 MPLX common units were acquired at a price of $0 per unit, suggesting a grant or similar non-cash award.

How many MPLX units does Frank M. Semple own directly after this transaction?

After the reported transaction, Frank M. Semple directly owns 57,100.516 MPLX LP common units.

What are Frank M. Semple’s indirect holdings of MPLX LP units?

Indirectly, Semple reports holding 333,337 units through the Frank M Semple Revocable Trust, 111,180 units through the Robin Y Semple 2012 Dynasty Trust, and 48,777 units through EK Holdings LLC.

What is Frank M. Semple’s relationship to MPLX LP?

Frank M. Semple is reported as a Director of MPLX GP LLC, which is the general partner that manages MPLX LP.

Does the Form 4 filing for MPLX include any derivative securities for Frank M. Semple?

The Form 4 includes a section for derivative securities, but no derivative securities transactions or holdings are reported for Frank M. Semple in that section.