---
schema_version: "secwatch.filing_event.v1"
accession: "0001552000-25-000040"
form_type: "8-K"
ticker: "MPLX"
cik: "0001552000"
company_name: "MPLX LP"
filed_at: "2025-11-04T23:59:59+00:00"
generated_at: "2026-05-17T00:37:16.966982+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# MPLX elects Maryann T. Mannen as Chairman; Michael J. Hennigan to retire as Executive Chairman effective Jan 1, 2026

## Summary
- Maryann T. Mannen elected Chairman of MPLX GP board effective Jan 1, 2026, in addition to her CEO role.
- Michael J. Hennigan to retire as Executive Chairman and board member effective Jan 1, 2026, reducing board size to 10.
- Chris Helms continues as independent lead director.
- Hennigan also retiring as executive chairman of MPC (Marathon Petroleum); Mannen to succeed as chairman of MPC effective Jan 1, 2026.

## SEC filing metadata
- accession: 0001552000-25-000040
- form_type: 8-K
- ticker: MPLX
- cik: 0001552000
- company_name: MPLX LP
- filed_at: 2025-11-04T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 5.02, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1552000/000155200025000040/0001552000-25-000040-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1552000/000155200025000040/mplx-20251029.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001552000-25-000040
- JSON: https://secwatch.observer/filing/0001552000-25-000040.json
- Plain text: https://secwatch.observer/filing/0001552000-25-000040.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.