MBX
MBX Biosciences, Inc. Common Stock · Healthcare · Biotechnology
Momentum inputs (comparable managers):
holder breadth -9.1% ·
share flow +20.3% ·
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 | 67 | +5 | 22.03M | $1.22B | +10 | −5 |
| Q1 2026 | 65 | +3 | 17.55M | $523.43M | +9 | −6 |
| Q4 2025 | 61 | +2 | 15.34M | $483.77M | +2 | — |
| Q3 2025 | 15 | +2 | 13.00M | $227.48M | +2 | — |
| Q2 2025 | 10 | -1 | 8.10M | $92.45M | +1 | −2 |
| Q1 2025 | 8 | 0 | 4.62M | $34.08M | +2 | −2 |
| Q4 2024 | 8 | -2 | 5.08M | $93.07M | — | −2 |
| Q3 2024 | 9 | +9 | 4.81M | $122.94M | +9 | — |
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | Wellington Management ✦ | 2.27M | -14.1% | $25.86M | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 2 | Wellington Management ✦ | 2.27M | -14.1% | $25.86M | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 3 | Wellington Management ✦ | 2.27M | -14.1% | $25.86M | 0.0% | ▼ Trim | 4 | SEC ↗ |
| 4 | T. Rowe Price ✦ | 1.35M | +22.3% | $15.37M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 5 | T. Rowe Price ✦ | 1.35M | +22.3% | $15.37M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 6 | The Vanguard Group ✦ (passive) | 1.04M | — | $11.91M | 0.0% | n/c | 1 | SEC ↗ |
| 7 | The Vanguard Group ✦ (passive) | 1.04M | — | $11.91M | 0.0% | n/c | 1 | SEC ↗ |
| 8 | The Vanguard Group ✦ (passive) | 1.04M | — | $11.91M | 0.0% | n/c | 1 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 1.01M | — | $11.54M | 0.0% | n/c | 1 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 1.01M | — | $11.54M | 0.0% | n/c | 1 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 1.01M | — | $11.54M | 0.0% | n/c | 1 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 1.01M | — | $11.54M | 0.0% | n/c | 1 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 1.01M | — | $11.54M | 0.0% | n/c | 1 | SEC ↗ |
| 14 | BlackRock ✦ (passive) | 1.01M | — | $11.54M | 0.0% | n/c | 1 | SEC ↗ |
| 15 | Point72 Asset Management ✦ | 973.79K | +781.4% | $11.11M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 16 | Millennium Management ✦ | 766.84K | +349.9% | $8.75M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 17 | Geode Capital Management ✦ (passive) | 348.45K | +27.0% | $3.98M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 18 | Geode Capital Management ✦ (passive) | 348.45K | +27.0% | $3.98M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 19 | State Street Global Advisors ✦ (passive) | 265.12K | +49.6% | $3.03M | 0.0% | ▲ Add | 3 | SEC ↗ |
| 20 | Fidelity (FMR) ✦ | 61.33K | — | $699,810 | 0.0% | n/c | 1 | SEC ↗ |
| 21 | AQR Capital Management ✦ | 18.00K | New | $205,392 | 0.0% | New | 1 | SEC ↗ |
| 22 | AQR Capital Management ✦ | 18.00K | New | $205,392 | 0.0% | New | 1 | SEC ↗ |
| 23 | AQR Capital Management ✦ | 18.00K | New | $205,392 | 0.0% | New | 1 | SEC ↗ |
| 24 | AQR Capital Management ✦ | 18.00K | New | $205,392 | 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
| AQR Capital Management | $205,392 | 0.0% |
| AQR Capital Management | $205,392 | 0.0% |
| AQR Capital Management | $205,392 | 0.0% |
| AQR Capital Management | $205,392 | 0.0% |
Exited
| Marshall Wace | $820,739 | was 0.0% |
| Two Sigma Investments | $249,688 | was 0.0% |
Full-market context: across ALL 13F filers (SEC structured data, Q1 2026): 156 holders, 52.39M shares, $1.53B 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.