UPB
Upstream Bio, Inc. · Healthcare · Biotechnology
Momentum inputs (comparable managers):
holder breadth +30.0% ·
share flow +30.0% ·
net new positions +20.0%
— formula
Broad accumulation — rising shares across more holders
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q4 2024
| Quarter | Holders | Δ | Shares | Reported value | New | Exits |
|---|---|---|---|---|---|---|
| Q2 2026 | 66 | +3 | 29.87M | $206.85M | +14 | −10 |
| Q1 2026 | 64 | +3 | 24.32M | $219.33M | +14 | −12 |
| Q4 2025 | 62 | +3 | 27.51M | $746.80M | +4 | — |
| Q3 2025 | 14 | +2 | 17.53M | $329.70M | +2 | −1 |
| Q2 2025 | 10 | -1 | 15.87M | $174.20M | +1 | −2 |
| Q1 2025 | 8 | +1 | 3.40M | $20.78M | +3 | −2 |
| Q4 2024 | 7 | +6 | 3.71M | $60.61M | +6 | — |
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | Wellington Management ✦ | 1.58M | New | $25.63M | 0.0% | New | 1 | SEC ↗ |
| 2 | Wellington Management ✦ | 1.58M | New | $25.63M | 0.0% | New | 1 | SEC ↗ |
| 3 | Wellington Management ✦ | 1.58M | New | $25.63M | 0.0% | New | 1 | SEC ↗ |
| 4 | Norges Bank ✦ (passive) | 1.00M | New | $16.44M | 0.0% | New | 1 | SEC ↗ |
| 5 | Geode Capital Management ✦ (passive) | 363.27K | New | $5.97M | 0.0% | New | 1 | SEC ↗ |
| 6 | Geode Capital Management ✦ (passive) | 363.27K | New | $5.97M | 0.0% | New | 1 | SEC ↗ |
| 7 | Marshall Wace ✦ | 290.73K | New | $4.78M | 0.0% | New | 1 | SEC ↗ |
| 8 | Marshall Wace ✦ | 290.73K | New | $4.78M | 0.0% | New | 1 | SEC ↗ |
| 9 | State Street Global Advisors ✦ (passive) | 247.19K | — | $4.06M | 0.0% | n/c | 1 | SEC ↗ |
| 10 | Citadel Advisors ✦ | 180.00K | New | $2.96M | 0.0% | New | 1 | SEC ↗ |
| 11 | Soros Fund Management ✦ | 46.35K | New | $761,994 | 0.0% | New | 1 | SEC ↗ |
“Their weight” = the position's share of that manager's reported 13F equity value — the conviction measure. ✦ = curated manager.
New buyers
| Wellington Management | $25.63M | 0.0% |
| Wellington Management | $25.63M | 0.0% |
| Wellington Management | $25.63M | 0.0% |
| Norges Bank | $16.44M | 0.0% |
| Geode Capital Management | $5.97M | 0.0% |
| Geode Capital Management | $5.97M | 0.0% |
| Marshall Wace | $4.78M | 0.0% |
| Marshall Wace | $4.78M | 0.0% |
| Citadel Advisors | $2.96M | 0.0% |
| Soros Fund Management | $761,994 | 0.0% |
Exited
| No tracked exits this quarter. |
Full-market context: across ALL 13F filers (SEC structured data, Q1 2026): 140 holders, 44.42M shares, $399.81M reported. This is a different, older period than the tracked-universe figures above and the two are never mixed.
What else this security's tracked holders most often hold — shared-ownership counts, not fundamental relationships.