Based on data from the past 90 days ending February 19, 2026, Upstream Bio's three largest insider shareholders are TenPercentOwner Upstream Llc Ai (5.49Mn shares), Director Advisors Llc Orbimed (4.55Mn shares), Director Erez Chimovits (4.55Mn shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Upstream Llc Ai | 5,494,410 | 17 Oct, 2024 | |
| Advisors Llc Orbimed | 4,554,873 | 17 Oct, 2024 | |
| Erez Chimovits | 4,554,873 | 17 Oct, 2024 | |
| Biomedical Innovation Master Investors (Cayman) Ii L.P. Wellington | 894,733 | 15 Oct, 2024 | |
| Everett Rand Sutherland | Chief Executive Officer | 75,000 | 06 Jan, 2026 |
| Aaron Deykin | Chief Medical Officer | 33,581 | 06 Jan, 2026 |
| Michael Gray | Cfo And Coo | 30,500 | 06 Jan, 2026 |
| Adam Houghton | Chief Business Officer | 25,000 | 06 Jan, 2026 |
| Allison Ambrose | General Counsel | 17,000 | 06 Jan, 2026 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 02 Jan, 2026 | Michael Gray | Common Stock | A | 30,500 | $0.00 | 30,500 | D | A |
| 02 Jan, 2026 | Everett Rand Sutherland | Common Stock | A | 75,000 | $0.00 | 75,000 | D | A |
| 02 Jan, 2026 | Adam Houghton | Common Stock | A | 25,000 | $0.00 | 25,000 | D | A |
| 02 Jan, 2026 | Aaron Deykin | Common Stock | A | 32,000 | $0.00 | 33,581 | D | A |
| 02 Jan, 2026 | Allison Ambrose | Common Stock | A | 17,000 | $0.00 | 17,000 | D | A |
| 15 Oct, 2024 | Advisors Llc Orbimed | - | - | 4,554,873 | I | |||
| 15 Oct, 2024 | Advisors Llc Orbimed | Common Stock | A | 660,000 | $17.00 | 4,554,873 | I | P |
| 15 Oct, 2024 | Advisors Llc Orbimed | Common Stock | A | 165,000 | $17.00 | 1,138,716 | I | P |
| 15 Oct, 2024 | Advisors Llc Orbimed | Common Stock | A | 2,887,833 | - | 3,894,873 | I | C |
| 15 Oct, 2024 | Advisors Llc Orbimed | - | - | 973,716 | I | |||
| 15 Oct, 2024 | Advisors Llc Orbimed | Common Stock | A | 721,956 | - | 973,716 | I | C |
| 15 Oct, 2024 | Erez Chimovits | Common Stock | A | 165,000 | $17.00 | 1,138,716 | I | P |
| 15 Oct, 2024 | Erez Chimovits | Common Stock | A | 721,956 | - | 973,716 | I | C |
| 15 Oct, 2024 | Erez Chimovits | Common Stock | A | 2,887,833 | - | 3,894,873 | I | C |
| 15 Oct, 2024 | Erez Chimovits | Common Stock | A | 660,000 | $17.00 | 4,554,873 | I | P |
| 15 Oct, 2024 | Biomedical Innovation Master Investors (Cayman) Ii L.P. Wellington | Common Stock | A | 894,733 | - | 894,733 | D | C |
| 15 Oct, 2024 | Upstream Llc Ai | Common Stock | A | 1,172,410 | - | 5,494,410 | D | C |
| 15 Oct, 2024 | Upstream Llc Ai | - | - | 4,322,000 | D | |||
| 15 Oct, 2024 | Upstream Llc Ai | Common Stock | A | 1,175,000 | $17.00 | 1,175,000 | D | P |
| 15 Oct, 2024 | Upstream Llc Ai | Common Stock | A | 3,147,000 | - | 4,322,000 | D | C |