Castle Biosciences, Inc. (CSTL) ownership: RTW Investments, LP 13% · institutions 84% · index and ETF funds 9% (13F 2026-03-31). Insider activity, 90 days: 59 sales, 0 open-market buys. 3 recent congressional STOCK Act disclosures. SEC EDGAR first-party data.
| Holder | Shares | Market Value | % Outstanding | Reported |
|---|---|---|---|---|
| BlackRock | 2982946.00 | $73.23M | 9.8% | 2026-03-31 |
| RTW Investments, LP | 2758335.00 | $67.72M | 9.0% | 2026-03-31 |
| Vanguard | 2264212.00 | $55.59M | 7.4% | 2026-03-31 |
| Principal Financial | 1769877.00 | $43.45M | 5.8% | 2026-03-31 |
| Portolan Capital Management, LLC | 1350283.00 | $33.15M | 4.4% | 2026-03-31 |
| Dimensional Fund Advisors | 1039761.00 | $25.52M | 3.4% | 2026-03-31 |
| Summit Partners Public Asset Management, LLC | 940685.00 | $23.09M | 3.1% | 2026-03-31 |
| Allianz (PIMCO) | 811324.00 | $19.92M | 2.7% | 2026-03-31 |
| Insider | Transaction | Value | Date |
|---|---|---|---|
| Sell | null | 2026-08-17 | |
| Sell | null | 2026-08-14 | |
| Sell | null | 2026-08-14 | |
| Sell | null | 2026-08-14 | |
| Sell | null | 2026-08-14 | |
| Sell | null | 2026-08-14 | |
| Sell | null | 2026-08-14 | |
| Sell | null | 2026-08-14 |
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Institutional data from SEC Form 13F. Insider data from SEC Form 4. Congressional data from STOCK Act disclosures. Not personalized investment advice.