Upstream Bio, Inc. has 7 Schedule 13D or 13G filings on record since 2025-08-06. 4 holders' latest filing reports 5% or more of common stock. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Fmr LLC | 14.8% | 7,936,880 | SCHEDULE 13G/A, 2025-08-06 | 2025-06-30 |
| Norges Bank | 7.73% | 4,206,586 | SCHEDULE 13G/A, 2026-08-12 | 2026-06-30 |
| BlackRock, Inc. | 5.2% | 2,814,714 | SCHEDULE 13G, 2026-07-30 | 2026-06-30 |
| Decheng Capital Global Life Sciences Fund IV, L.P. | 5% | 2,724,868 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| HBM Healthcare Investments (Cayman) Ltd. | 4.1% | 2,195,111 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
| TCG Crossover GP I, LLC | 3.9% | 2,117,103 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-06 | Fmr LLC | 14.8% | SCHEDULE 13G/A |
| 2025-10-24 | Norges Bank | 5.3% | SCHEDULE 13G |
| 2025-11-14 | HBM Healthcare Investments (Cayman) Ltd. | 4.1% | SCHEDULE 13G/A |
| 2025-11-14 | TCG Crossover GP I, LLC | 3.9% | SCHEDULE 13G/A |
| 2026-05-15 | Decheng Capital Global Life Sciences Fund IV, L.P. | 5% | SCHEDULE 13G/A |
| 2026-07-30 | BlackRock, Inc. | 5.2% | SCHEDULE 13G |
| 2026-08-12 | Norges Bank | 7.73% | SCHEDULE 13G/A |
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.