Garry L. Peiffer - 14 Aug 2026 Form 4 Insider Report for MPLX LP (MPLX)

Reporting relationship: Director
Issuer ticker: MPLX
Reported as of: 14 Aug 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 18 Aug 2026, 17:31:04 UTC
Prior SEC filing: 19 May 2026
Source filing: View source filing
Reporting owner signature: /s/ Molly R. Benson, Attorney-in-Fact for Garry L. Peiffer

Key filing fact

Garry L. Peiffer filed Form 4 for MPLX LP (MPLX) on 18 Aug 2026.

Key facts

This page summarizes Garry L. Peiffer's Form 4 filing for MPLX LP (MPLX).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 18 Aug 2026, 17:31.

Change

Previous filing in this sequence was filed on 19 May 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001521094 Primary reporting owner

Peiffer Garry L.

Relationship: Director
Address: C/O MPLX LP, 200 E. HARDIN STREET, FINDLAY
Signature: /s/ Molly R. Benson, Attorney-in-Fact for Garry L. Peiffer
Signature date: 18 Aug 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MPLX transaction

Common Units (Limited Partner Interests)

Award

Transaction value
Shares: +1,232
Change %: +1.8%
Price: $0.000000^*
Shares after: 69,313
Date: 14 Aug 2026
Ownership: Direct

MPLX holding

Common Units (Limited Partner Interests)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 68,497
Date: 14 Aug 2026
Ownership: By Revocable Trust
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

By Garry L. and Kathleen J. Peiffer Trust, created on April 24, 2026.

SEC 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.