Mplx LP (MPLX) Shareholders & Insider Trades
Mplx shareholders at a glance
The largest holder of Mplx stock is Marathon Petroleum Corporation, with 647.4 million shares (63.86% of the company), worth about $38.31 billion as of September 25, 2026. The 10 largest holders together own 74.3%.
In Q2 2026, 653 institutional holdings reports listed 196.0 million shares worth $11.10 billion, down 3.4% in shares from Q1 2026.
Insiders reported 77 transactions in the last two years: 1 sale worth $188,960 and 1 purchase. The newest one on file is from April 30, 2026 (Peiffer Garry L, Director).
Major holders as of September 25, 2026; quarterly totals from institutional holdings reports (latest Q2 2026); insider transactions on file through April 30, 2026.
Mplx LP
Shareholders Summary
2026Q2
Ownership by Type
Geographic Distribution
Largest Mplx shareholders
| Holder | Shares | % of company | Value |
|---|---|---|---|
| Marathon Petroleum Corporation | 647.4 million | 63.86% | $38.3B |
| ALPS Advisors, Inc. (Subfiler) | 28.6 million | 2.82% | $1.7B |
| Invesco Advisers, Inc. | 18.3 million | 1.80% | $1.1B |
| Harvest Fund Advisors LLC | 13.0 million | 1.28% | $767.0M |
| Goldman Sachs Asset Management LP | 11.3 million | 1.12% | $670.0M |
| Tortoise Capital Advisors LLC | 10.5 million | 1.04% | $621.0M |
| Mirae Asset Global ETFs Holdings Ltd. | 8.0 million | 0.79% | $474.0M |
| KA Fund Advisors LLC | 5.9 million | 0.58% | $347.0M |
| Energy Income Partners LLC | 5.4 million | 0.53% | $318.0M |
| UBS Financial Services, Inc. | 5.3 million | 0.52% | $311.0M |
As of September 25, 2026.
Mplx institutional holdings by quarter
| Quarter | Reports | Shares | Value |
|---|---|---|---|
| Q2 2026 | 653 | 196.0 million | $11.1B |
| Q1 2026 | 660 | 203.0 million | $11.6B |
| Q4 2025 | 650 | 179.0 million | $9.6B |
| Q3 2025 | 596 | 215.0 million | $10.7B |
| Q2 2025 | 599 | 218.0 million | $11.2B |
| Q1 2025 | 590 | 226.0 million | $12.1B |
| Q4 2024 | 555 | 222.0 million | $10.4B |
| Q3 2024 | 523 | 238.0 million | $10.6B |
Shares and value held by institutions that file quarterly holdings reports (options not included).
Mplx insider trades
| Insider | Date | Title | Transaction | Value |
|---|---|---|---|---|
| Peiffer Garry L | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Breves Christine S | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Stice J Michael Ed.D. | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Semple Frank M | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Surma John P Jr. | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Walker Ray N Jr | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Helms Christopher A | Apr 30, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Mannen Maryann T | Feb 27, 2026 | Chief Executive Officer | Stock Award(Grant) at price 0.00 per share. | – |
| Khoury Maria A. | Feb 27, 2026 | Director | Stock Award(Grant) at price 0.00 per share. | – |
| Hagedorn Carl Kristopher | Feb 27, 2026 | Officer and Director | Stock Award(Grant) at price 0.00 per share. | – |
| Lyon Shawn M. | Feb 27, 2026 | Officer | Stock Award(Grant) at price 0.00 per share. | – |
| Benson Molly R. | Feb 27, 2026 | Officer | Stock Award(Grant) at price 0.00 per share. | – |
Newest 12 of 77 insider transactions in the last two years.
Questions and answers
Who owns the most Mplx stock?
Marathon Petroleum Corporation, with 63.86% of the company (as of September 25, 2026). Next: ALPS Advisors, Inc. (Subfiler) (2.82%) and Invesco Advisers, Inc. (1.80%).
How many institutions own Mplx stock?
653 institutional holdings reports listed Mplx shares in Q2 2026, 196.0 million shares in all worth $11.10 billion.
Are Mplx insiders buying or selling the stock?
In the last two years insiders reported 1 sale and 1 purchase (77 transactions in all); the newest on file is from April 30, 2026.
