4 institutions reported holding $85.3M of ARCELORMITTAL SA LUXEMBOURG (MT.WS) in SEC 13F filings for 2026-06-30. Largest institutional holders: Optiver Holding B.V. ($65.4M), GROUP ONE TRADING LLC ($8.0M), SIMPLEX TRADING, LLC ($7.7M), IMC-Chicago, LLC ($4.1M). Source: SEC Form 13F.
| Rank | Institution | Value | Shares | Change |
|---|---|---|---|---|
| 1 | Optiver Holding B.V. | $65.4M | 1.1M | Trimmed |
| 2 | GROUP ONE TRADING LLC | $8.0M | 133,200 | Trimmed |
| 3 | SIMPLEX TRADING, LLC | $7.7M | 128,200 | Trimmed |
| 4 | IMC-Chicago, LLC | $4.1M | 68,300 | Trimmed |
Source: SEC Form 13F filings · as of 2026-06-30