4 institutions reported holding $30.0M of GARTNER INC (IT.B) in SEC 13F filings for 2026-06-30. Largest institutional holders: IMC-Chicago, LLC ($20.6M), SIMPLEX TRADING, LLC ($6.2M), GROUP ONE TRADING LLC ($3.3M), HUNTINGTON NATIONAL BANK ($10). Source: SEC Form 13F.
| Rank | Institution | Value | Shares | Change |
|---|---|---|---|---|
| 1 | IMC-Chicago, LLC | $20.6M | 158,700 | Added |
| 2 | SIMPLEX TRADING, LLC | $6.2M | 47,500 | Added |
| 3 | GROUP ONE TRADING LLC | $3.3M | 25,400 | Added |
| 4 | HUNTINGTON NATIONAL BANK | $10 | 1 | Hold |
Source: SEC Form 13F filings · as of 2026-06-30