MARATHON PETE (MPC) Institutional Ownership & Top Holders
The most recent SEC Form 13F filings (Q2 2026) show 5 hedge funds and institutional investors holding a combined 235K shares of MARATHON PETE (MPC), valued at $60.2M. The median portfolio weight is 0.0%.
The latest institutional ownership changes for MPC show net selling, with the combined position down by 2.6M shares (91.7%) from the previous quarter.
Among 13F filers, the funds with the highest portfolio allocation to MPC are Harris Associates (0.1% of its 13F portfolio), CastleKnight (0.0%), and UTIMCO - The University of Texas (0.0%). In Q2 2026, CastleKnight made the largest position increase (+0.0%), while Panview Capital made the largest reduction (-1.1%).
Top 5 Institutional Holders in MARATHON PETE (MPC), Ranked by Portfolio Weight
Based on the latest SEC Form 13F filings (Q2 2026).
| # | Fund | Shares | Market Value | Portfolio Weight |
|---|---|---|---|---|
| 1 | Harris Associates | 229,011 | $58.6M | 0.1% |
| 2 | CastleKnight | 3,200 | $818K | 0.0% |
| 3 | UTIMCO - The University of Texas | 863 | $221K | 0.0% |
| 4 | Matrix Asset Advisors | 854 | $218K | 0.0% |
| 5 | Mairs & Power | 1,390 | $355K | 0.0% |
- 5Institutional investors
- 235,318Shares held (disclosed)
- $60.2M13F market value
- 0.0%Median portfolio weight
Ownership History
Quarter-by-quarter share count, market value, and portfolio conviction weight (up to 5 of the heaviest weight-by-portfolio funds) of MPC. Sourced from 13F filings; reflects long equity positions only.
Quarter-over-Quarter ActivityQ2 2026
The biggest weight-increase and weight-decrease changes among funds that hold MPC. Deltas compare the selected filing to the previous reporting quarter.
Top buyers
- CastleKnight+0.0% · +3,200 shares
Top sellers
- Panview Capital-1.1% · -21,805 shares
- Harris Associates-0.8% · -2,576,961 shares
- UTIMCO - The University of Texas-0.7% · -20,421 shares
Options Activity
- Total calls40,000 (+40,000)
Ownership Statistics
- Funds holding
- 5
- Median weight
- 0.0%
- Largest holder
- Harris Associates · 0.1%
- Smallest holder
- Mairs & Power · 0.0%
- Shares held
- 235,318 (-2,615,987)
All Institutional HoldersSortable · searchable
All institutional investors (Max 50) holding MPC in the selected quarter. Click a fund name to drill into its full 13F portfolio.
| 1 | Harris Associates | 229,011 | $58.6M | 0.1% |
| 2 | CastleKnight | 3,200 | $818.1K | 0.0% |
| 3 | UTIMCO - The University of Texas | 863 | $220.6K | 0.0% |
| 4 | Matrix Asset Advisors | 854 | $218.3K | 0.0% |
| 5 | Mairs & Power | 1,390 | $355.4K | 0.0% |
Institutional Investor Count Over Time
Number of institutional investors disclosing a long position in MARATHON PETE CORP (MPC) each reporting quarter. Sourced from SEC Form 13F-HR filings.
See MARATHON PETE CORP (MPC) insider transactions (SEC Form 4) →
Methodology & FAQ
Methodology: How We Track MPC Institutional Holdings
Our data is systematically aggregated directly from quarterly Form 13F-HR disclosures submitted to the U.S. Securities and Exchange Commission (SEC).
- Who must file: This dataset includes filings from U.S. institutional investment managers, hedge funds, mutual funds, university endowments, and family offices managing at least $100 million in Section 13(f) securities (including equities, options, convertibles, ETFs, and warrants).
- What is included: We capture long positions in Section 13(f) securities for MARATHON PETE CORP (MPC). By SEC regulation, 13F filings do not require the disclosure of short positions, non-U.S. holdings, or OTC derivatives. Listed options are excluded from portfolio weight calculations to ensure comparability across filers.
- Metric definition: “Portfolio Weight” shows how much of a fund's total reported 13F portfolio value (excluding listed options) is allocated to MPC on the specific reporting date.
- How to use this data: Quarter-over-quarter changes in shares and portfolio weight reflect a combination of active trading and market price movements. These are descriptive metrics of fund allocation, not explicit buy or sell signals.
How do you measure hedge fund conviction and institutional concentration in MPC?
We evaluate fund conviction by looking at portfolio weight rather than just absolute share count. By tracking how the largest holders , such as Harris Associates , CastleKnight , and UTIMCO - The University of Texas as of Q2 2026, change their position sizing quarter-over-quarter, we help investors distinguish between deliberate position sizing changes and passive mark-to-market drift.
Does the MPC ownership data include short interest or options?
SEC Form 13F mandates the disclosure of long positions in Section 13(f) securities, which includes equities and listed options (put and call contracts), but excludes short interest, swaps, and OTC derivatives by regulatory design. On this platform, listed options are excluded from portfolio weight calculations to ensure comparability across filers.
Are family offices and university endowments included in this MPC data?
Yes. In addition to traditional hedge funds and large asset managers, any institutional entity exercising investment discretion over at least $100 million in Section 13(f) securities must file a Form 13F. This explicitly includes single-family offices and university endowments. If a qualifying family office or endowment holds MPC stock, their allocation is systematically aggregated alongside traditional fund data.
When is the institutional ownership data updated, and is there a reporting lag?
Institutional investment managers are required to file their Form 13F within 45 days after the end of a calendar quarter (the standard “T+45” window). Our platform re-ingests new filings from the SEC EDGAR database on a nightly cycle, typically within 24–48 hours of publication, providing a point-in-time snapshot of reported consensus positioning for MPC as of each filing date.