Security record · archived quarter
MBX
MBX Biosciences, Inc. Common Stock · Healthcare · Biotechnology
15Tracked holders
+2Δ holders
13.00MShares held
$227.48MReported value
+2New positions
−0Exits
Momentum inputs (comparable managers):
holder breadth +15.4% ·
share flow +30.0% ·
net new positions +13.3%
— formula
Broad accumulation — rising shares across more holders
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q3 2025
Ownership over time
| 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 | — |
Who holds it · Q3 2025
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | Wellington Management ✦ | 4.82M | +112.8% | $84.41M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 2 | Wellington Management ✦ | 4.82M | +112.8% | $84.41M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 3 | Wellington Management ✦ | 4.82M | +112.8% | $84.41M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 4 | Wellington Management ✦ | 4.82M | +112.8% | $84.41M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 5 | Wellington Management ✦ | 4.82M | +112.8% | $84.41M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 6 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 7 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 8 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 1.96M | +93.5% | $34.26M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 14 | The Vanguard Group ✦ (passive) | 1.68M | +60.7% | $29.35M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 15 | The Vanguard Group ✦ (passive) | 1.68M | +60.7% | $29.35M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 16 | The Vanguard Group ✦ (passive) | 1.68M | +60.7% | $29.35M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 17 | Citadel Advisors ✦ | 996.08K | New | $17.43M | 0.0% | New | 1 | SEC ↗ |
| 18 | Citadel Advisors ✦ | 996.08K | New | $17.43M | 0.0% | New | 1 | SEC ↗ |
| 19 | T. Rowe Price ✦ | 954.73K | -29.1% | $16.71M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 20 | T. Rowe Price ✦ | 954.73K | -29.1% | $16.71M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 21 | Millennium Management ✦ | 655.42K | -14.5% | $11.47M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 22 | Point72 Asset Management ✦ | 627.67K | -35.5% | $10.98M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 23 | Geode Capital Management ✦ (passive) | 473.93K | +36.0% | $8.30M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 24 | Geode Capital Management ✦ (passive) | 473.93K | +36.0% | $8.30M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 25 | Goldman Sachs Group ✦ | 358.12K | — | $6.27M | 0.0% | n/c | 1 | SEC ↗ |
| 26 | Goldman Sachs Group ✦ | 358.12K | — | $6.27M | 0.0% | n/c | 1 | SEC ↗ |
| 27 | State Street Global Advisors ✦ (passive) | 319.27K | +20.4% | $5.59M | 0.0% | ▲ Add | 4 | SEC ↗ |
| 28 | Fidelity (FMR) ✦ | 68.98K | +12.5% | $1.21M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 29 | Morgan Stanley ✦ | 44.87K | — | $785,191 | 0.0% | n/c | 1 | SEC ↗ |
| 30 | Morgan Stanley ✦ | 44.87K | — | $785,191 | 0.0% | n/c | 1 | SEC ↗ |
| 31 | Morgan Stanley ✦ | 44.87K | — | $785,191 | 0.0% | n/c | 1 | SEC ↗ |
| 32 | Morgan Stanley ✦ | 44.87K | — | $785,191 | 0.0% | n/c | 1 | SEC ↗ |
| 33 | AQR Capital Management ✦ | 15.76K | -12.4% | $275,871 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 34 | AQR Capital Management ✦ | 15.76K | -12.4% | $275,871 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 35 | AQR Capital Management ✦ | 15.76K | -12.4% | $275,871 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 36 | AQR Capital Management ✦ | 15.76K | -12.4% | $275,871 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 37 | Two Sigma Investments ✦ | 13.59K | New | $237,773 | 0.0% | New | 1 | SEC ↗ |
| 38 | JPMorgan Chase ✦ | 12.35K | — | $216,126 | 0.0% | n/c | 1 | SEC ↗ |
| 39 | JPMorgan Chase ✦ | 12.35K | — | $216,126 | 0.0% | n/c | 1 | SEC ↗ |
“Their weight” = the position's share of that manager's reported 13F equity value — the conviction measure. ✦ = curated manager.
New buyers
| Citadel Advisors | $17.43M | 0.0% |
| Citadel Advisors | $17.43M | 0.0% |
| Two Sigma Investments | $237,773 | 0.0% |
Exited
| No tracked exits this quarter. |
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.
Frequently co-owned
What else this security's tracked holders most often hold — shared-ownership counts, not fundamental relationships.
Provenance: Ownership from parsed 13F common-stock positions (tracked universe, comparable sets for changes); insider rows from Forms 3/4/5; stakes from Schedules 13D/13G; every filing links to its original on SEC EDGAR.
Reporting period: Q3 2025 ·
Methodology ·
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