UPB
Upstream Bio, Inc. · Healthcare · Biotechnology
Momentum inputs (comparable managers):
holder breadth -9.1% ·
share flow +1.7% ·
net new positions -10.0%
· formula
Concentrated accumulation: rising shares among fewer holders
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q2 2025
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | Fidelity (FMR) ✦ | 7.94M | n/a | $87.15M | 0.0% | n/c | 1 | SEC ↗ ×5 |
| 2 | The Vanguard Group ✦ (passive) | 2.17M | n/a | $23.84M | 0.0% | n/c | 1 | SEC ↗ ×3 |
| 3 | BlackRock ✦ (passive) | 2.10M | n/a | $23.02M | 0.0% | n/c | 1 | SEC ↗ ×7 |
| 4 | Wellington Management ✦ | 1.23M | -6.7% | $13.45M | 0.0% | ▼ Trim | 3 | SEC ↗ ×2 |
| 5 | Norges Bank ✦ (passive) | 969.92K | 0.0% | $10.65M | 0.0% | Held | 3 | SEC ↗ |
| 6 | Geode Capital Management ✦ (passive) | 646.63K | +57.5% | $7.10M | 0.0% | ▲ Add | 3 | SEC ↗ ×2 |
| 7 | State Street Global Advisors ✦ (passive) | 481.38K | +62.9% | $5.29M | 0.0% | ▲ Add | 3 | SEC ↗ |
| 8 | Marshall Wace ✦ | 290.53K | -4.7% | $3.19M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 9 | AQR Capital Management ✦ | 29.75K | +58.1% | $326,677 | 0.0% | ▲ Add | 2 | SEC ↗ ×5 |
| 10 | T. Rowe Price ✦ | 17.45K | New | $192,000 | 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
| T. Rowe Price | $192,000 | 0.0% |
Exited
| Millennium Management | $378,192 | was 0.0% |
| Two Sigma Investments | $133,349 | was 0.0% |
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.
Open-market purchases (P)
No open-market insider purchases in our coverage window.
Open-market sales (S)
Officer · 485 sh · $2,663
Officer · 895 sh · $4,914
Officer · 853 sh · $4,683
Officer · 700 sh · $3,843
Awards, exercises and tax withholding are never counted as buys or sales here. Methodology