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
| 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 | Fidelity (FMR) ✦ | 7.94M | — | $87.15M | 0.0% | n/c | 1 | SEC ↗ |
| 2 | Fidelity (FMR) ✦ | 7.94M | — | $87.15M | 0.0% | n/c | 1 | SEC ↗ |
| 3 | Fidelity (FMR) ✦ | 7.94M | — | $87.15M | 0.0% | n/c | 1 | SEC ↗ |
| 4 | Fidelity (FMR) ✦ | 7.94M | — | $87.15M | 0.0% | n/c | 1 | SEC ↗ |
| 5 | Fidelity (FMR) ✦ | 7.94M | — | $87.15M | 0.0% | n/c | 1 | SEC ↗ |
| 6 | The Vanguard Group ✦ (passive) | 2.17M | — | $23.84M | 0.0% | n/c | 1 | SEC ↗ |
| 7 | The Vanguard Group ✦ (passive) | 2.17M | — | $23.84M | 0.0% | n/c | 1 | SEC ↗ |
| 8 | The Vanguard Group ✦ (passive) | 2.17M | — | $23.84M | 0.0% | n/c | 1 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 14 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 15 | BlackRock ✦ (passive) | 2.10M | — | $23.02M | 0.0% | n/c | 1 | SEC ↗ |
| 16 | Wellington Management ✦ | 1.23M | -6.7% | $13.45M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 17 | Wellington Management ✦ | 1.23M | -6.7% | $13.45M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 18 | Norges Bank ✦ (passive) | 969.92K | 0.0% | $10.65M | 0.0% | Held | 3 | SEC ↗ |
| 19 | Geode Capital Management ✦ (passive) | 646.63K | +57.5% | $7.10M | 0.0% | ▲ Add | 3 | SEC ↗ |
| 20 | Geode Capital Management ✦ (passive) | 646.63K | +57.5% | $7.10M | 0.0% | ▲ Add | 3 | SEC ↗ |
| 21 | State Street Global Advisors ✦ (passive) | 481.38K | +62.9% | $5.29M | 0.0% | ▲ Add | 3 | SEC ↗ |
| 22 | Marshall Wace ✦ | 290.53K | -4.7% | $3.19M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 23 | AQR Capital Management ✦ | 29.75K | +58.1% | $326,677 | 0.0% | ▲ Add | 2 | SEC ↗ |
| 24 | AQR Capital Management ✦ | 29.75K | +58.1% | $326,677 | 0.0% | ▲ Add | 2 | SEC ↗ |
| 25 | AQR Capital Management ✦ | 29.75K | +58.1% | $326,677 | 0.0% | ▲ Add | 2 | SEC ↗ |
| 26 | AQR Capital Management ✦ | 29.75K | +58.1% | $326,677 | 0.0% | ▲ Add | 2 | SEC ↗ |
| 27 | AQR Capital Management ✦ | 29.75K | +58.1% | $326,677 | 0.0% | ▲ Add | 2 | SEC ↗ |
| 28 | 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.