3 institutions reported holding $1.1M of MAGNOLIA OIL & GAS CORP (MGY.WS) in SEC 13F filings for 2026-06-30. Largest institutional holders: IMC-Chicago, LLC ($823,676), GROUP ONE TRADING LLC ($171,386), SIMPLEX TRADING, LLC ($61,392). Source: SEC Form 13F.
| Rank | Institution | Value | Shares | Change |
|---|---|---|---|---|
| 1 | IMC-Chicago, LLC | $823,676 | 32,200 | New |
| 2 | GROUP ONE TRADING LLC | $171,386 | 6,700 | Added |
| 3 | SIMPLEX TRADING, LLC | $61,392 | 2,400 | Trimmed |
Source: SEC Form 13F filings · as of 2026-06-30