CSTL
Castle Biosciences, Inc. · Healthcare · Medical - Diagnostics & Research
Momentum inputs (comparable managers):
holder breadth -7.1% ·
share flow -0.9% ·
net new positions -7.7%
— formula
Broad distribution — falling shares and 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 | 76 | -1 | 16.76M | $400.39M | +6 | −6 |
| Q1 2026 | 79 | -9 | 16.13M | $395.93M | +4 | −13 |
| Q4 2025 | 87 | +2 | 17.12M | $665.58M | +2 | — |
| Q3 2025 | 16 | 0 | 9.41M | $214.29M | +1 | −1 |
| Q2 2025 | 13 | -1 | 9.39M | $191.81M | — | −1 |
| Q1 2025 | 11 | 0 | 4.13M | $82.76M | +1 | −1 |
| Q4 2024 | 11 | +2 | 4.84M | $128.97M | +4 | −2 |
| Q3 2024 | 8 | 0 | 2.64M | $75.25M | — | — |
| Q2 2024 | 8 | — | 1.95M | $42.47M | — | — |
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 2 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 3 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 4 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 5 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 6 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 7 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 8 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 9 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 10 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 11 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 12 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 13 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 14 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 15 | BlackRock ✦ (passive) | 3.15M | — | $64.42M | 0.0% | n/c | 1 | SEC ↗ |
| 16 | The Vanguard Group ✦ (passive) | 2.17M | — | $44.31M | 0.0% | n/c | 1 | SEC ↗ |
| 17 | The Vanguard Group ✦ (passive) | 2.17M | — | $44.31M | 0.0% | n/c | 1 | SEC ↗ |
| 18 | The Vanguard Group ✦ (passive) | 2.17M | — | $44.31M | 0.0% | n/c | 1 | SEC ↗ |
| 19 | The Vanguard Group ✦ (passive) | 2.17M | — | $44.31M | 0.0% | n/c | 1 | SEC ↗ |
| 20 | The Vanguard Group ✦ (passive) | 2.17M | — | $44.31M | 0.0% | n/c | 1 | SEC ↗ |
| 21 | Citadel Advisors ✦ | 888.51K | +243.9% | $18.14M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 22 | Citadel Advisors ✦ | 888.51K | +243.9% | $18.14M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 23 | State Street Global Advisors ✦ (passive) | 707.69K | -1.0% | $14.45M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 24 | Geode Capital Management ✦ (passive) | 689.93K | +6.2% | $14.09M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 25 | Geode Capital Management ✦ (passive) | 689.93K | +6.2% | $14.09M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 26 | Renaissance Technologies ✦ | 670.50K | -4.4% | $13.69M | 0.0% | ▼ Trim | 5 | SEC ↗ |
| 27 | Millennium Management ✦ | 428.40K | +68.2% | $8.75M | 0.0% | ▲ Add | 5 | SEC ↗ |
| 28 | Wellington Management ✦ | 407.21K | -50.9% | $8.32M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 29 | Wellington Management ✦ | 407.21K | -50.9% | $8.32M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 30 | Wellington Management ✦ | 407.21K | -50.9% | $8.32M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 31 | Wellington Management ✦ | 407.21K | -50.9% | $8.32M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 32 | D. E. Shaw & Co. ✦ | 148.19K | -21.7% | $3.03M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 33 | AQR Capital Management ✦ | 49.23K | -64.1% | $1.01M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 34 | AQR Capital Management ✦ | 49.23K | -64.1% | $1.01M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 35 | AQR Capital Management ✦ | 49.23K | -64.1% | $1.01M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 36 | AQR Capital Management ✦ | 49.23K | -64.1% | $1.01M | 0.0% | ▼ Trim | 3 | SEC ↗ |
| 37 | Two Sigma Investments ✦ | 28.24K | -79.8% | $576,681 | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 38 | T. Rowe Price ✦ | 26.41K | +11.4% | $540,000 | 0.0% | ▲ Add | 5 | SEC ↗ |
| 39 | Fidelity (FMR) ✦ | 24.00K | — | $490,080 | 0.0% | n/c | 1 | SEC ↗ |
| 40 | Fidelity (FMR) ✦ | 24.00K | — | $490,080 | 0.0% | n/c | 1 | SEC ↗ |
| 41 | Fidelity (FMR) ✦ | 24.00K | — | $490,080 | 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
| No new tracked buyers this quarter. |
Exited
| Point72 Asset Management | $4.73M | was 0.0% |
Full-market context: across ALL 13F filers (SEC structured data, Q1 2026): 186 holders, 27.52M shares, $653.08M 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 · 1.73K sh · $51,191
Officer, Director · 1.10K sh · $33,022
Officer, Director · 2.71K sh · $81,474
Officer, Director · 2.31K sh · $69,226
Officer, Director · 278 sh · $8,346
Officer · 24.91K sh · $741,511
Awards, exercises and tax withholding are never counted as buys or sales here. Methodology