MARATHON OIL CORP (MRO) Top Institutional Shareholders
MARATHON OIL CORP (MRO) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended March 31, 2026. The institutional investors covered on this page collectively reported approximately $10.74M in MRO holdings during the latest filing period.
Storebrand Asset Management As is currently the largest disclosed institutional shareholder of MRO tracked by InsiderSet, reporting ownership valued at approximately $6.88M in its December 31, 2021 SEC Form 13F filing.
The top 10 institutional shareholders tracked on this page collectively account for approximately 100% of the total disclosed MRO value among the investors covered in this analysis. Major shareholders include Storebrand Asset Management As, Ramiah Investment Group, Independent Financial Group, Llc, and several other long-term asset managers with concentrated positions in MARATHON OIL CORP (MRO).
This page ranks the largest institutional MRO shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
5
Total Reported Value
$10.74M
Largest Holder
Storebrand Asset Management As
Largest Position
$6.88M
Insider Transactions (90d)
0
Latest Filing Quarter
Q1 2026
New Institutional Positions
14
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Storebrand Asset Management As | 0.00% | 274,416 | $6,883,226 | — | — | — | |
| Ramiah Investment Group | 0.16% | 168,884 | $2,300,200 | — | — | — | |
| Independent Financial Group, Llc | 0.02% | 80,538 | $1,551,839 | — | — | — | |
| Kentucky Retirement Systems | 0.15% | 57,515 | $2,030 | — | — | — | |
| Huntington National Bank | 0.00% | 1 | $29 | — | — | — |
Frequently asked questions about MRO
Who owns the most MRO stock?
The largest holders of MRO are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for MARATHON OIL CORP (MRO).
Is MRO widely held by superinvestors?
Many widely followed stocks like MRO appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly MRO is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.