| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| FMR LLC | 15% | +11% | $93,972,663 | +$9,006,605 | 7,936,880 | +11% | FMR LLC | 30 Jun 2025 |
| Decheng Capital Global Life Sciences Fund IV, L.P. | 6.1% | $29,501,931 | 3,285,293 | Xiangmin Cui | 31 Dec 2024 | |||
| NORGES BANK | 5.3% | $54,226,626 | 2,882,647 | Norges Bank | 30 Sep 2025 | |||
| HBM Healthcare Investments (Cayman) Ltd. | 4.1% | -20% | $41,290,257 | -$9,780,217 | 2,195,111 | -19% | HBM Healthcare Investments (Cayman) Ltd. | 30 Sep 2025 |
| TCG Crossover GP I, LLC | 3.9% | -26% | $39,822,919 | -$12,878,523 | 2,117,103 | -24% | TCG Crossover GP I, LLC | 30 Sep 2025 |
As of 31 Dec 2025, 129 institutional investors reported holding 51,161,942 shares of Upstream Bio, Inc. - Common Stock, par value $0.001 per share (UPB). This represents 94% of the company’s total 54,284,692 outstanding shares.
The largest institutional shareholders of Upstream Bio, Inc. - Common Stock, par value $0.001 per share (UPB) together control 84% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| FMR LLC | 14% | 7,518,202 | -7% | 0.01% | $204,119,193 |
| ORBIMED ADVISORS LLC | 10% | 5,693,589 | 0% | 3.3% | $154,580,941 |
| BlackRock, Inc. | 6.2% | 3,344,504 | +28% | 0% | $90,803,284 |
| Decheng Capital LLC | 5.8% | 3,143,078 | -4.3% | 11% | $85,334,568 |
| NORGES BANK | 5.3% | 2,882,647 | 0.01% | $78,263,866 | |
| ENAVATE SCIENCES GP, LLC | 4.5% | 2,459,703 | 0% | 13% | $66,780,936 |
| VANGUARD GROUP INC | 4.4% | 2,388,439 | -2.2% | 0% | $64,846,119 |
| UBS Group AG | 3.3% | 1,806,243 | +563% | 0.01% | $49,039,498 |
| JANUS HENDERSON GROUP PLC | 2.8% | 1,527,958 | 0.02% | $41,422,941 | |
| Altshuler Shaham Ltd | 2.5% | 1,341,540 | -5.3% | 0.56% | $36,422,811 |
| Bain Capital Life Sciences Investors, LLC | 2.4% | 1,329,544 | -46% | 2.8% | $36,097,120 |
| Omega Fund Management, LLC | 2.4% | 1,326,293 | -2.2% | 13% | $36,008,855 |
| STATE STREET CORP | 2.4% | 1,319,226 | +18% | 0% | $35,816,986 |
| VR ADVISER, LLC | 2.2% | 1,169,298 | 0% | 1.6% | $31,746,441 |
| WELLINGTON MANAGEMENT GROUP LLP | 1.6% | 894,733 | -20% | 0% | $24,292,001 |
| GEODE CAPITAL MANAGEMENT, LLC | 1.6% | 851,908 | +4.3% | 0% | $23,134,004 |
| Parkman Healthcare Partners LLC | 1.5% | 834,559 | -1.1% | 2.2% | $22,658,277 |
| Pictet Asset Management Holding SA | 1.4% | 773,148 | 0.02% | $20,990,968 | |
| Woodline Partners LP | 1.4% | 760,252 | +26% | 0.08% | $20,640,842 |
| Integral Health Asset Management, LLC | 1.4% | 750,000 | +30% | 1% | $20,362,500 |
| TCG Crossover Management, LLC | 1.4% | 743,886 | -65% | 0.67% | $20,196,505 |
| SAMSARA BIOCAPITAL, LLC | 1.4% | 736,047 | -24% | 2.1% | $19,983,676 |
| Vestal Point Capital, LP | 1.3% | 720,000 | 0.72% | $19,548,000 | |
| Siren, L.L.C. | 1.1% | 588,450 | -25% | 0.48% | $15,976,418 |
| BARCLAYS PLC | 0.97% | 524,499 | +515% | 0.01% | $14,240,148 |
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2025 Q4 | 51,161,942 | $1,388,991,725 | +$177,854,919 | $27.15 | 129 |
| 2025 Q3 | 44,461,719 | $836,327,467 | -$50,813,162 | $18.81 | 94 |
| 2025 Q2 | 48,353,677 | $530,923,062 | +$32,738,813 | $10.98 | 82 |
| 2025 Q1 | 42,073,968 | $257,482,324 | -$17,702,490 | $6.12 | 76 |
| 2024 Q4 | 42,074,592 | $690,108,943 | +$649,643,232 | $16.44 | 70 |