---
schema_version: "secwatch.filing_event.v1"
accession: "0001552000-24-000017"
form_type: "8-K"
ticker: "MPLX"
cik: "0001552000"
company_name: "MPLX LP"
filed_at: "2024-05-13T23:59:59+00:00"
generated_at: "2026-06-02T02:18:37.770878+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# MPLX announces CEO succession: Maryann Mannen to become President and CEO effective Aug 1, 2024

## Summary
- Maryann T. Mannen succeeds Michael J. Hennigan as President and CEO of the general partner, effective August 1, 2024.
- Hennigan becomes Executive Chairman of the board; Christopher A. Helms remains independent Lead Director.
- Mannen will also serve as President and CEO of parent Marathon Petroleum (MPC) as of the same date.
- Under Hennigan's CEO tenure, MPLX returned approx. $15B to unitholders via distributions and buybacks.

## SEC filing metadata
- accession: 0001552000-24-000017
- form_type: 8-K
- ticker: MPLX
- cik: 0001552000
- company_name: MPLX LP
- filed_at: 2024-05-13T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 5.02, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1552000/000155200024000017/0001552000-24-000017-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1552000/000155200024000017/mplx-20240511.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001552000-24-000017
- JSON: https://secwatch.observer/filing/0001552000-24-000017.json
- Plain text: https://secwatch.observer/filing/0001552000-24-000017.txt

## Key facts
- Executive change
  Maryann T. Mannen was appointed as President and Chief Executive Officer at MPLX LP.
  - Action: appointed
  - Role: President and Chief Executive Officer
  source text: appointed Maryann T. Mannen as President and Chief Executive Officer, effective August 1, 2024.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1552000/000155200024000017/0001552000-24-000017-index.htm
- Executive change
  Michael J. Hennigan was elected as Executive Chairman at MPLX LP.
  - Action: elected
  - Role: Executive Chairman
  source text: Mr. Hennigan has been elected Executive Chairman of MPLX GP’s board of directors
  evidence_url: https://www.sec.gov/Archives/edgar/data/1552000/000155200024000017/0001552000-24-000017-index.htm

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