Who owns Upstream Bio, Inc.?
Institutional ownership of UPB from SEC Form 13F filings across 111 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.
111
13F holders
$231.7M
value, 2026 filers
62.2%
of shares outstanding (33.9M sh)
29
new positions (2026 filers)
Top institutional holders
ordered by shares owned · positions as of 2026-06-30· % of fund = share of the manager's own book · % of co. = share of UPB's shares outstanding
| # | Manager | Shares | Value | % of fund | % of co. | Δ shares QoQ |
|---|---|---|---|---|---|---|
| 1 | FMR LLC | 8.2M | $56.5M | 0.0% | 15% | +0.8% |
| 2 | NORGES BANKNEW | 3.8M | $26.1M | 0.0% | 6.9% | new |
| 3 | BlackRock, Inc. | 3.8M | $26.0M | 0.0% | 6.9% | +11.4% |
| 4 | VANGUARD CAPITAL MANAGEMENT LLC | 1.9M | $13.0M | 0.0% | 3.4% | -49.9% |
| 5 | MILLENNIUM MANAGEMENT LLC | 1.1M | $7.9M | 0.0% | 2.1% | +22.0% |
| 6 | D. E. Shaw & Co., Inc. | 1.0M | $7.2M | 0.0% | 1.9% | +26.3% |
| 7 | JPMORGAN CHASE & CO | 1.0M | $7.0M | 0.0% | 1.9% | +118.6% |
| 8 | Qube Research & Technologies Ltd | 978,500 | $6.8M | 0.0% | 1.8% | +58.0% |
| 9 | GEODE CAPITAL MANAGEMENT, LLC | 931,261 | $6.4M | 0.0% | 1.7% | -2.0% |
| 10 | SEB Asset Management AB | 878,473 | $6.1M | 0.0% | 1.6% | 0.0% |
| 11 | Woodline Partners LP | 831,481 | $5.8M | 0.0% | 1.5% | -50.0% |
| 12 | VANGUARD PORTFOLIO MANAGEMENT LLC | 712,667 | $4.9M | 0.0% | 1.3% | -2.1% |
| 13 | Y-Intercept (Hong Kong) Ltd | 693,555 | $4.8M | 0.1% | 1.3% | -30.7% |
| 14 | MORGAN STANLEY | 524,632 | $3.6M | 0.0% | 1% | -5.1% |
| 15 | BNP PARIBAS FINANCIAL MARKETS | 511,546 | $3.5M | 0.0% | 0.9% | +306.0% |
| 16 | Walleye Capital LLCNEW | 498,490 | $3.4M | 0.0% | 0.9% | new |
| 17 | Point72 Asset Management, L.P. | 453,011 | $3.1M | 0.0% | 0.8% | +154.3% |
| 18 | BANK OF AMERICA CORP /DE/ | 391,762 | $2.7M | 0.0% | 0.7% | +708.4% |
| 19 | Altshuler Shaham Ltd | 380,061 | $2.6M | 0.0% | 0.7% | 0.0% |
| 20 | ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 357,756 | $2.5M | 0.0% | 0.7% | +93.3% |
| 21 | WELLINGTON MANAGEMENT GROUP LLP | 342,353 | $2.4M | 0.0% | 0.6% | 0.0% |
| 22 | NORTHERN TRUST CORP | 297,346 | $2.1M | 0.0% | 0.5% | +13.9% |
| 23 | Squarepoint Ops LLC | 290,904 | $2.0M | 0.0% | 0.5% | +551.9% |
| 24 | Voleon Capital Management LPNEW | 285,234 | $2.0M | 0.0% | 0.5% | new |
| 25 | Sixth Street Partners Management Company, L.P.NEW | 262,456 | $1.8M | 0.3% | 0.5% | new |
Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.