Upstream BioUPB
13F holders, Q4 2025 (December 31)133holders +38
41new positions
8sold out
5famous investors
$27.15avg. 13F price*
At the end of Q4 2025, 133 institutions reported holding Upstream Bio Inc. (UPB) in their 13F filings, up 38 from Q3 2025. 41 opened new positions and 8 sold out. The largest holders were FMR LLC ($204.1M), Orbimed Advisors LLC ($154.6M) and BlackRock, Inc. ($90.8M). 5 famous investors held it, including Israel Englander (0.0% of Millennium Management's portfolio), Jim Simons / Peter Brown (0.0% of Renaissance Technologies's portfolio) and David E. Shaw (0.0% of D. E. Shaw & Co.'s portfolio).
- Company
- Upstream Bio Inc.
- CUSIP
- 91678A107
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q3 2025 → Q4 2025
| Institutions | Total Value | |
|---|---|---|
| New Positions | 41 | $118.6M |
| Exits | 8 | $6.8M |
All 13F filers, Q3 2025 → Q4 2025: 8,760,733 shares bought and 5,189,880 shares sold, net +3,570,853 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 133 holders
| FMR LLC | 0.01% | Reduce -7.0% | 7,518,202 | $204.1M |
| Orbimed Advisors LLC | 3.16% | No change | 5,693,589 | $154.6M |
| BlackRock, Inc. | 0.00% | Add +28.4% | 3,344,504 | $90.8M |
| Decheng Capital LLC | 11.48% | Reduce -4.3% | 3,143,078 | $85.3M |
| Norges Bank | 0.01% | — | 2,882,647 | $78.3M |
| Enavate Sciences Gp, LLC | 13.18% | No change | 2,459,703 | $66.8M |
| Vanguard Group Inc. | 0.00% | Reduce -2.2% | 2,388,439 | $64.8M |
| UBS Group AG | 0.01% | Add +563.4% | 1,806,243 | $49.0M |
| Janus Henderson Group PLC | 0.02% | New | 1,527,958 | $41.4M |
| Altshuler Shaham Ltd | 0.56% | Reduce -5.3% | 1,341,540 | $36.4M |
| Bain Capital Life Sciences Investors, LLC | 2.77% | Reduce -45.5% | 1,329,544 | $36.1M |
| Omega Fund Management, LLC | 12.57% | Reduce -2.2% | 1,326,293 | $36.0M |
| State Street Corp. | 0.00% | Add +18.4% | 1,319,226 | $35.8M |
| Venrock Adviser, LLC | 1.57% | No change | 1,169,298 | $31.7M |
| Wellington Management Group LLP | 0.00% | Reduce -20.5% | 894,733 | $24.3M |
| Geode Capital Management, LLC | 0.00% | Add +4.3% | 851,908 | $23.1M |
| Parkman Healthcare Partners LLC | 2.16% | Reduce -1.1% | 834,559 | $22.7M |
| Pictet Asset Management Holding SA | 0.02% | New | 773,148 | $21.0M |
| Woodline Partners LP | 0.08% | Add +26.2% | 760,252 | $20.6M |
| Integral Health Asset Management, LLC | 1.03% | Add +30.4% | 750,000 | $20.4M |
| TCG Crossover Management, LLC | 0.67% | Reduce -64.9% | 743,886 | $20.2M |
| Samsara Biocapital, LLC | 2.06% | Reduce -23.5% | 736,047 | $20.0M |
| Vestal Point Capital, LP | 0.72% | New | 720,000 | $19.5M |
| Siren, L.L.C. | 0.48% | Reduce -25.4% | 588,450 | $16.0M |
| Barclays PLC | 0.01% | Add +514.8% | 524,499 | $14.2M |
| Millennium Management | 0.01% | Add +1189.5% | 517,264 | $14.0M |
| Nantahala Capital Management, LLC | 0.80% | Reduce -16.8% | 494,971 | $13.4M |
| Marshall Wace, LLP | 0.01% | Reduce -60.4% | 343,791 | $9.3M |
| Goldman Sachs Group Inc. | 0.00% | Add +49.4% | 333,481 | $9.1M |
| Great Point Partners LLC | 2.64% | No change | 300,000 | $8.1M |
| Alyeska Investment Group, L.P. | 0.02% | New | 298,329 | $8.1M |
| Jennison Associates LLC | 0.00% | New | 288,847 | $7.8M |
| Charles Schwab Investment Management Inc. | 0.00% | Add +0.0% | 284,931 | $7.7M |
| Northern Trust Corp. | 0.00% | Reduce -7.0% | 236,799 | $6.4M |
| Squadron Capital Management LLC | 2.79% | — | 230,650 | $6.3M |
| Invesco Ltd. | 0.00% | Add +849.3% | 163,186 | $4.4M |
| Boxer Capital Management, LLC | 0.89% | New | 150,000 | $4.1M |
| Deutsche Bank AG | 0.00% | Add +378.1% | 127,815 | $3.5M |
| Morgan Stanley | 0.00% | Add +39.5% | 122,068 | $3.3M |
| SummitTX Capital, L.P. | 0.10% | Add +3.8% | 116,724 | $3.2M |
| Schonfeld Strategic Advisors LLC | 0.02% | Reduce -39.1% | 115,807 | $3.1M |
| JPMorgan Chase & Co. | 0.00% | Add +268.3% | 110,280 | $3.0M |
| American Century Companies Inc. | 0.00% | Add +22.7% | 87,756 | $2.4M |
| Bank of America Corp. | 0.00% | Add +55.7% | 86,384 | $2.3M |
| Bank of New York Mellon Corp | 0.00% | Reduce -7.3% | 84,853 | $2.3M |
| Nuveen, LLC | 0.00% | Add +12.4% | 78,568 | $2.1M |
| ExodusPoint Capital Management, LP | 0.02% | New | 75,402 | $2.0M |
| Artia Global Partners LP | 0.30% | New | 68,653 | $1.9M |
| Exome Asset Management LLC | 0.87% | Add +24.8% | 64,845 | $1.8M |
| Ameriprise Financial Inc. | 0.00% | New | 56,557 | $1.5M |
| Susquehanna International Group, LLP | 0.00% | New | 55,841 | $1.5M |
| Seven Grand Managers, LLC | 0.10% | New | 50,000 | $1.4M |
| Y-Intercept (Hong Kong) Ltd | 0.03% | New | 46,559 | $1.3M |
| Alps Advisors Inc. | 0.01% | Add +70.9% | 44,376 | $1.2M |
| Rhumbline Advisers | 0.00% | Reduce -16.0% | 41,523 | $1.1M |
| Rafferty Asset Management, LLC | 0.00% | Add +12.1% | 38,683 | $1.1M |
| Wells Fargo & Company | 0.00% | Add +46.2% | 36,794 | $999K |
| Trexquant Investment LP | 0.01% | New | 31,049 | $843K |
| Alliancebernstein L.P. | 0.00% | Add +56.2% | 31,010 | $842K |
| AQR Capital Management | 0.00% | Add +1.8% | 30,503 | $828K |
| D. E. Shaw & Co. | 0.00% | New | 27,091 | $736K |
| Swiss National Bank | 0.00% | New | 26,600 | $722K |
| Diadema Partners LP | 0.33% | New | 20,500 | $557K |
| MetLife Investment Management, LLC | 0.00% | Reduce -9.3% | 19,678 | $534K |
| T. Rowe Price Associates Inc. | 0.00% | Add +6.1% | 19,636 | $534K |
| PSP Research LLC | 0.42% | — | 17,634 | $479K |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. | 0.00% | Add +3.7% | 17,491 | $475K |
| Prelude Capital Management, LLC | 0.03% | Add +5.2% | 16,560 | $450K |
| Renaissance Technologies | 0.00% | New | 16,400 | $445K |
| Quantinno Capital Management LP | 0.00% | Add +3.5% | 15,415 | $419K |
| XTX Topco Ltd | 0.01% | New | 15,091 | $410K |
| California State Teachers Retirement System | 0.00% | Add +573.4% | 14,652 | $398K |
| Profund Advisors LLC | 0.01% | New | 14,582 | $396K |
| Graham Capital Management, L.P. | 0.02% | New | 13,712 | $372K |
| Legal & General Group Plc | 0.00% | Add +368.8% | 13,709 | $372K |
| Citadel Advisors | 0.00% | New | 13,420 | $364K |
| DNB Asset Management AS | 0.00% | New | 12,793 | $347K |
| Virtu Financial LLC | 0.01% | New | 12,246 | $332K |
| Verition Fund Management LLC | 0.00% | Reduce -74.4% | 12,020 | $326K |
| Mariner, LLC | 0.00% | Add +8.2% | 11,830 | $321K |
| Creative Planning | 0.00% | Reduce -17.6% | 11,749 | $319K |
| New York State Common Retirement Fund | 0.00% | Add +85.7% | 11,700 | $318K |
| Two Sigma Investments, LP | 0.00% | No change | 10,500 | $285K |
| Intech Investment Management LLC | 0.00% | No change | 10,396 | $282K |
| Manufacturers Life Insurance Company, The | 0.00% | Reduce -16.1% | 10,147 | $275K |
| Virtus Investment Advisers, LLC | 0.07% | Reduce -0.4% | 9,801 | $266K |
| STRS Ohio | 0.00% | New | 9,800 | $266K |
| VARCOV Co. | 0.10% | — | 9,619 | $261K |
| Police & Firemen's Retirement System of New Jersey | 0.00% | Add +0.1% | 9,456 | $257K |
| Persistent Asset Partners Ltd | 0.12% | New | 8,907 | $242K |
| China Universal Asset Management Co., Ltd. | 0.02% | New | 8,806 | $239K |
| ProShare Advisors LLC | 0.00% | New | 8,354 | $227K |
| Sei Investments Co. | 0.00% | New | 8,087 | $220K |
| Citigroup Inc. | 0.00% | Reduce -83.5% | 6,949 | $189K |
| SG Americas Securities, LLC | 0.00% | New | 5,518 | $150K |
| BNP Paribas Financial Markets | 0.00% | Reduce -23.8% | 4,976 | $135K |
| Cwm, LLC | 0.00% | Add +0.6% | 3,360 | $91K |
| KLP Kapitalforvaltning As | 0.00% | New | 2,900 | $79K |
| Russell Investments Group, Ltd. | 0.00% | Reduce -7.0% | 2,823 | $77K |
| Ameritas Investment Partners, Inc. | 0.00% | No change | 2,741 | $74K |
"% of holder's portfolio" is UPB's weight in each manager's 13F, not the share of Upstream Bio Inc. the manager owns.