Castle Biosciences Inc
CSTL- Exchange
- Nasdaq
- Industry
- Services-Medical Laboratories
- SEC CIK
- 0001447362
In the last 90 days, Castle Biosciences Inc insiders filed 0 open-market purchases and 20 sales; 176 institutions reported holding it in 13F filings for Q2 2026, worth $653.8M in total; no superinvestor holds it.
13F holders, Q4 2025
Institutional positions in Castle Biosciences Inc as of Dec 31, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works
- Institutional holders
- 195
- +26 vs. Q3 2025
- Shares held
- 27.3M
- +724.4K (+2.7%) vs. Q3 2025
- Total value
- $1.06B
- +$455.1M (+75.0%) vs. Q3 2025
- New holders
- 43
- 64 more added
- Sold out
- 17
- 69 more reduced
4 institutions that held it in Q3 2025 haven't filed for Q4 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q3 2025: new holders, sold out and not filed yet
Holders and value by quarter
Institutions reporting CSTL on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.
| Quarter | Holders | Value |
|---|---|---|
| Q2 2026 | 176 | $653.8M |
| Q1 2026 | 186 | $677.8M |
| Q4 2025 | 195 | $1.06B |
| Q3 2025 | 173 | $608.3M |
| Q2 2025 | 152 | $541.8M |
| Q1 2025 | 180 | $516.3M |
| Q4 2024 | 197 | $706.4M |
| Q3 2024 | 185 | $736.9M |
| Q2 2024 | 159 | $549.4M |
| Q1 2024 | 151 | $553.2M |
| Q4 2023 | 153 | $515.4M |
| Q3 2023 | 135 | $391.0M |
| Q2 2023 | 130 | $316.6M |
| Q1 2023 | 148 | $501.9M |
| Q4 2022 | 153 | $522.0M |
| Q3 2022 | 157 | $569.8M |
| Q2 2022 | 146 | $495.0M |
| Q1 2022 | 160 | $1.02B |
| Q4 2021 | 159 | $918.6M |
| Q3 2021 | 188 | $1.42B |
| Q2 2021 | 182 | $1.52B |
| Q1 2021 | 175 | $1.46B |
Institutions, Q4 2025
Shares, value and share of portfolio for each institution holding Castle Biosciences Inc; share changes are against Q3 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| Susquehanna International Group, LLP | 0 | $0 | 0.00% | −24,225−100.0% | Sold out |
| Brevan Howard Capital Management LP | 0 | $0 | 0.00% | −19,128−100.0% | Sold out |
| Capstone Investment Advisors, LLC | 0 | $0 | 0.00% | −16,677−100.0% | Sold out |
| Bailard, Inc. | 0 | $0 | 0.00% | −11,400−100.0% | Sold out |
| Magnetar Financial LLC | 0 | $0 | 0.00% | −10,327−100.0% | Sold out |
| Atom Investors LP | 0 | $0 | 0.00% | −9,827−100.0% | Sold out |
| Simplex Trading, LLC | 0 | $0 | 0.00% | −1,512−100.0% | Sold out |
| Group One Trading, L.P. | 0 | $0 | 0.00% | −803−100.0% | Sold out |
| Principal Securities, Inc. | 0 | $0 | 0.00% | −76−100.0% | Sold out |
| Optiver Holding B.V. | 0 | $0 | 0.00% | −40−100.0% | Sold out |
| Clearstead Advisors, LLC | 0 | $0 | 0.00% | −12−100.0% | Sold out |
| Advisory Services Network, LLC | 0 | $0 | 0.00% | −7−100.0% | Sold out |
| Cubist Systematic Strategies, LLC | – | – | – | – | Not filed |
| Glenmede Investment Management, LP | – | – | – | – | Not filed |
| Point72 (DIFC) Ltd | – | – | – | – | Not filed |
| Point72 Europe (London) LLP | – | – | – | – | Not filed |