UPSTREAM BIO INC CALL is a security (CUSIP 91678A907) tracked across SEC portfolio filings. 2 institutional managers reported $340K on Form 13F as of 2026-03-31.
| Manager | Location | Value | Shares |
|---|---|---|---|
| SIMPLEX TRADING, LLC | CHICAGO, IL | $251K | — |
| GROUP ONE TRADING, L.P. | CHICAGO, IL | $89K | — |