MPLX director granted 2,246.989 common units

Peiffer Garry L. reported acquisition or exercise transactions in this Form 4 filing.

Accepted by SEC EDGAR 05/04/2026 - 05:11 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Peiffer Garry L. reported acquisition or exercise transactions in this Form 4 filing.

MPLX LP director Garry L. Peiffer received an equity compensation award of 2,246.989 common units of MPLX LP on April 30, 2026. The award was granted at $0.00 per unit as his annual 2026 equity retainer, so it was not an open-market purchase.

After this grant, Peiffer directly holds 66,319.332 common units. Separately, 68,497 common units are reported as indirectly held through the Garry L. Peiffer Revocable Trust.

Insider Trade Summary

Grant/Award: 2,246.989 shares

Grant/Award 1 txn

Insider Peiffer Garry L.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Common Units (Limited Partner Interests)	2,246.989	$0.00	$0.00
Holding	Common Units (Limited Partner Interests)	--	--	--

Holdings After Transaction: Common Units (Limited Partner Interests) — 66,319.332 shares (Direct); Common Units (Limited Partner Interests) — 68,497 shares (Indirect, By Revocable Trust)

Footnotes (2)

1. F1. Represents the reporting person's annual 2026 equity retainer award.
2. F2. By Garry L. Peiffer Revocable Trust.

Key Figures

Equity retainer award: 2,246.989 common units Grant price: $0.00 per unit Direct holdings after grant: 66,319.332 common units +1 more

4 metrics

Equity retainer award 2,246.989 common units Annual 2026 equity retainer granted on April 30, 2026

Grant price $0.00 per unit Price for 2026 equity retainer award units

Direct holdings after grant 66,319.332 common units Direct ownership following April 30, 2026 grant

Indirect trust holdings 68,497 common units Held through Garry L. Peiffer Revocable Trust as of April 30, 2026

Key Terms

Common Units (Limited Partner Interests), equity retainer award, Revocable Trust, Form 4

4 terms

Common Units (Limited Partner Interests) financial

"security_title: "Common Units (Limited Partner Interests)""

equity retainer award financial

"Represents the reporting person's annual 2026 equity retainer award."

Revocable Trust financial

"By Garry L. Peiffer Revocable Trust."

A revocable trust is a legal arrangement where the person who creates it keeps control and can change or cancel the trust at any time, while naming who will manage and receive the assets later. Think of it like a flexible folder for your investments and property that can be relabeled or reworked as circumstances change; it matters to investors because it determines how ownership is recorded, how easily assets transfer on incapacity or death, and whether holdings bypass public probate proceedings.

Form 4 regulatory

"INSIDER FILING DATA (Form 4): {"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did MPLX (MPLX) director Garry L. Peiffer report in this Form 4?

Garry L. Peiffer reported receiving an equity compensation grant of 2,246.989 MPLX common units. The award represents his annual 2026 equity retainer and was issued at $0.00 per unit, meaning it was compensation, not an open-market purchase of units.

How many MPLX units were granted to Garry L. Peiffer on April 30, 2026?

Peiffer was granted 2,246.989 MPLX common units on April 30, 2026. The filing identifies this as his annual 2026 equity retainer award, issued at $0.00 per unit as part of director compensation rather than a market transaction.

Are Garry L. Peiffer’s MPLX units from this Form 4 a market purchase or compensation?

The 2,246.989 MPLX common units are compensation, not a market purchase. The Form 4 describes them as Peiffer’s annual 2026 equity retainer award, granted at $0.00 per unit as part of his service as a director of MPLX LP.

How many MPLX units does Garry L. Peiffer directly own after this transaction?

Following the April 30, 2026 equity grant, Peiffer directly holds 66,319.332 MPLX common units. This total reflects his direct ownership only; additional units are reported separately as indirectly owned through the Garry L. Peiffer Revocable Trust.

What MPLX holdings are reported through the Garry L. Peiffer Revocable Trust?

The Form 4 reports 68,497 MPLX common units as indirectly owned through the Garry L. Peiffer Revocable Trust. This entry is labeled as a holding, indicating units associated with the revocable trust rather than a new purchase or sale on the transaction date.

Does this MPLX Form 4 show any insider sales by Garry L. Peiffer?

The Form 4 does not report any sales by Peiffer. It shows an acquisition of 2,246.989 MPLX common units as an equity retainer award and a separate indirect holding entry for 68,497 units held through the Garry L. Peiffer Revocable Trust.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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
Estimated average burden
hours per response:			0.5

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^*

Peiffer Garry L.

(Last) (First) (Middle)

C/O MPLX LP

200 E. HARDIN STREET

(Street)

FINDLAY OHIO 45840

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/30/2026

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

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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

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)	04/30/2026		A		2,246.989(1)	A	$0	66,319.332	D
Common Units (Limited Partner Interests)								68,497	I	By Revocable Trust(2)

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:

1. Represents the reporting person's annual 2026 equity retainer award.

2. By Garry L. Peiffer Revocable Trust.

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 Garry L. Peiffer	05/04/2026
	** 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.
* Form 4: SEC 1474 (03-26)