Upstream BioUPB
13F holders, Q1 2026 (March 31)140holders +7
40new positions
37sold out
6famous investors
$9.01avg. 13F price*
At the end of Q1 2026, 140 institutions reported holding Upstream Bio Inc. (UPB) in their 13F filings, up 7 from Q4 2025. 40 opened new positions and 37 sold out. The largest holders were FMR LLC ($72.9M), Orbimed Advisors LLC ($51.2M) and BlackRock, Inc. ($30.3M). 6 famous investors held it, including Israel Englander (0.0% of Millennium Management's portfolio), David E. Shaw (0.0% of D. E. Shaw & Co.'s portfolio) and Steve Cohen (0.0% of Point72 Asset Management's portfolio).
- Company
- Upstream Bio Inc.
- CUSIP
- 91678A107
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q4 2025 → Q1 2026
| Institutions | Total Value | |
|---|---|---|
| New Positions | 40 | $32.1M |
| Exits | 37 | $202.3M |
All 13F filers, Q4 2025 → Q1 2026: 9,105,845 shares bought and 13,854,610 shares sold, net −4,748,765 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 140 holders
| FMR LLC | 0.00% | Add +7.8% | 8,101,563 | $72.9M |
| Orbimed Advisors LLC | 1.16% | No change | 5,693,589 | $51.2M |
| BlackRock, Inc. | 0.00% | Add +0.8% | 3,370,689 | $30.3M |
| Decheng Capital LLC | 3.71% | Reduce -13.3% | 2,724,868 | $24.5M |
| Enavate Sciences Gp, LLC | 6.30% | No change | 2,459,703 | $22.1M |
| Vanguard Capital Management LLC | 0.00% | — | 1,873,574 | $16.9M |
| Y-Intercept (Hong Kong) Ltd | 0.17% | Add +2049.2% | 1,000,631 | $9.0M |
| Federated Hermes, Inc. | 0.01% | Add +203169.3% | 979,758 | $8.8M |
| Geode Capital Management, LLC | 0.00% | Add +11.6% | 950,617 | $8.6M |
| Millennium Management | 0.01% | Add +81.2% | 937,323 | $8.4M |
| SEB Asset Management AB | 0.03% | — | 878,473 | $7.9M |
| Bain Capital Life Sciences Investors, LLC | 0.71% | Reduce -34.8% | 867,211 | $7.8M |
| Woodline Partners LP | 0.03% | Add +9.4% | 831,481 | $7.5M |
| D. E. Shaw & Co. | 0.01% | Add +2928.6% | 820,480 | $7.4M |
| Parkman Healthcare Partners LLC | 0.73% | Reduce -5.7% | 786,783 | $7.1M |
| Samsara Biocapital, LLC | 0.64% | No change | 736,047 | $6.6M |
| Pictet Asset Management Holding SA | 0.01% | Reduce -5.1% | 733,431 | $6.6M |
| Vanguard Portfolio Management LLC | 0.00% | — | 727,711 | $6.5M |
| State Street Corp. | 0.00% | Reduce -46.5% | 705,350 | $6.3M |
| HSBC Holdings PLC | 0.00% | New | 640,326 | $5.8M |
| Qube Research & Technologies Ltd | 0.01% | New | 619,321 | $5.6M |
| Morgan Stanley | 0.00% | Add +352.7% | 552,609 | $5.0M |
| JPMorgan Chase & Co. | 0.00% | Add +319.8% | 463,001 | $4.1M |
| Nantahala Capital Management, LLC | 0.23% | Reduce -19.2% | 400,000 | $3.6M |
| Altshuler Shaham Ltd | 0.06% | Reduce -71.7% | 380,061 | $3.4M |
| Sphera Funds Management LTD. | 0.55% | New | 358,000 | $3.2M |
| Propel Bio Management, LLC | 1.95% | New | 341,779 | $3.1M |
| Wellington Management Group LLP | 0.00% | Reduce -61.7% | 342,353 | $3.1M |
| Jump Financial, LLC | 0.05% | New | 319,400 | $2.9M |
| Goldman Sachs Group Inc. | 0.00% | Reduce -5.1% | 316,587 | $2.8M |
| Alyeska Investment Group, L.P. | 0.01% | No change | 298,329 | $2.7M |
| Northern Trust Corp. | 0.00% | Add +10.2% | 260,992 | $2.3M |
| Charles Schwab Investment Management Inc. | 0.00% | Reduce -9.6% | 257,729 | $2.3M |
| Prosight Management, LP | 0.36% | New | 241,123 | $2.2M |
| UBS Group AG | 0.00% | Reduce -87.2% | 231,254 | $2.1M |
| Vanguard Fiduciary Trust Co. | 0.00% | — | 224,157 | $2.0M |
| XTX Topco Ltd | 0.03% | Add +1286.8% | 209,277 | $1.9M |
| Arrowstreet Capital, Limited Partnership | 0.00% | New | 185,087 | $1.7M |
| TCG Crossover Management, LLC | 0.05% | Reduce -75.7% | 181,063 | $1.6M |
| Deutsche Bank AG | 0.00% | Add +41.5% | 180,889 | $1.6M |
| Point72 Asset Management | 0.00% | New | 178,168 | $1.6M |
| Trexquant Investment LP | 0.01% | Add +469.0% | 176,657 | $1.6M |
| Schonfeld Strategic Advisors LLC | 0.01% | Add +39.3% | 161,349 | $1.5M |
| Boxer Capital Management, LLC | 0.18% | No change | 150,000 | $1.4M |
| BNP Paribas Financial Markets | 0.00% | Add +2432.2% | 126,000 | $1.1M |
| Alliancebernstein L.P. | 0.00% | No change | 31,010 | $842K |
| ExodusPoint Capital Management, LP | 0.01% | Add +21.3% | 91,431 | $823K |
| American Century Companies Inc. | 0.00% | Reduce -0.1% | 87,624 | $789K |
| Bank of New York Mellon Corp | 0.00% | Reduce -4.1% | 81,383 | $732K |
| Dimensional Fund Advisors LP | 0.00% | New | 80,002 | $719K |
| Simplify Asset Management Inc. | 0.01% | New | 77,793 | $700K |
| Nuveen, LLC | 0.00% | Reduce -3.9% | 75,536 | $680K |
| EntryPoint Capital, LLC | 0.19% | New | 73,568 | $662K |
| AQR Capital Management | 0.00% | Add +136.6% | 72,171 | $650K |
| Marshall Wace, LLP | 0.00% | Reduce -80.6% | 66,770 | $601K |
| Renaissance Technologies | 0.00% | Add +278.7% | 62,100 | $559K |
| Quantinno Capital Management LP | 0.00% | Add +220.4% | 49,389 | $445K |
| Bank of America Corp. | 0.00% | Reduce -43.9% | 48,460 | $436K |
| Swiss National Bank | 0.00% | Add +80.8% | 48,100 | $433K |
| Squarepoint Ops LLC | 0.00% | New | 44,626 | $402K |
| Alps Advisors Inc. | 0.00% | Reduce -0.9% | 43,992 | $396K |
| State of Wisconsin Investment Board | 0.00% | New | 41,671 | $375K |
| Rhumbline Advisers | 0.00% | Reduce -0.8% | 41,203 | $371K |
| Invesco Ltd. | 0.00% | Reduce -75.2% | 40,510 | $365K |
| California State Teachers Retirement System | 0.00% | Add +170.7% | 39,661 | $357K |
| Gsa Capital Partners LLP | 0.02% | New | 39,232 | $353K |
| Stonepine Capital Management, LLC | 0.28% | New | 35,000 | $315K |
| ADAR1 Capital Management, LLC | 0.02% | New | 35,000 | $315K |
| Aquatic Capital Management LLC | 0.01% | New | 31,484 | $283K |
| Bleakley Financial Group, LLC | 0.00% | New | 28,864 | $260K |
| Axq Capital, LP | 0.03% | New | 27,503 | $248K |
| Mariner, LLC | 0.00% | Add +130.9% | 27,314 | $246K |
| T. Rowe Price Associates Inc. | 0.00% | Add +34.6% | 26,434 | $238K |
| Tudor Investment Corporation | 0.00% | New | 26,412 | $238K |
| Martingale Asset Management L P | 0.01% | New | 26,223 | $236K |
| Victory Capital Management Inc. | 0.00% | New | 25,866 | $233K |
| Barclays PLC | 0.00% | Reduce -95.3% | 24,720 | $222K |
| DNB Asset Management AS | 0.00% | Add +83.8% | 23,515 | $212K |
| Entropy Technologies, LP | 0.01% | New | 23,336 | $210K |
| Diadema Partners LP | 0.08% | Add +5.4% | 21,609 | $194K |
| Man Group plc | 0.00% | New | 21,154 | $190K |
| Nisa Investment Advisors, LLC | 0.00% | Add +4789.5% | 19,558 | $176K |
| MetLife Investment Management, LLC | 0.00% | Reduce -1.5% | 19,380 | $174K |
| Wells Fargo & Company | 0.00% | Reduce -50.0% | 18,402 | $166K |
| Susquehanna International Group, LLP | 0.00% | Reduce -71.4% | 15,961 | $144K |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. | 0.00% | Reduce -10.8% | 15,608 | $140K |
| Manufacturers Life Insurance Company, The | 0.00% | Add +51.2% | 15,338 | $138K |
| Franklin Resources Inc. | 0.00% | New | 14,589 | $131K |
| Vanguard Global Advisers, LLC | 0.00% | — | 13,059 | $118K |
| Corient Private Wealth LP | 0.00% | New | 12,157 | $109K |
| Creative Planning | 0.00% | Reduce -7.7% | 10,850 | $98K |
| Virtus Investment Advisers, LLC | 0.02% | Add +2.5% | 10,046 | $90K |
| Shay Capital LLC | 0.01% | New | 10,000 | $90K |
| STRS Ohio | 0.00% | No change | 9,800 | $88K |
| Legal & General Group Plc | 0.00% | Reduce -29.9% | 9,609 | $86K |
| China Universal Asset Management Co., Ltd. | 0.01% | Add +8.9% | 9,590 | $86K |
| Police & Firemen's Retirement System of New Jersey | 0.00% | No change | 9,456 | $85K |
| VANGUARD ASSET MANAGEMENT, Ltd | 0.00% | — | 9,250 | $83K |
| KLP Kapitalforvaltning As | 0.00% | Add +103.5% | 5,900 | $53K |
| Persistent Asset Partners Ltd | 0.02% | Reduce -38.3% | 5,495 | $49K |
"% of holder's portfolio" is UPB's weight in each manager's 13F, not the share of Upstream Bio Inc. the manager owns.