CASTLE BIOSCIENCES INC (CSTL) Institutional Ownership Changes & 13F Activity
CASTLE BIOSCIENCES INC (CSTL). Institutional ownership data tracks hedge funds, asset managers, and other institutional investors based on recent SEC Form 13F filings (Q4 2025). This page analyzes institutional buying and selling activity, new holdings, and sold-out positions in the latest reporting period. Notable filers include Rtw Investments, Lp, Portolan Capital Management, Llc, Summit Partners Public Asset Management, Llc, Palisade Capital Management, Lp, and Citadel Advisors Llc.
| Institution | Type | Change in shares | Change Position % | Shares | Reported stock balance | Portfolio quarter | Filing date |
|---|---|---|---|---|---|---|---|
| Algert Global Llc | Sell | -38,917 | -67.2% | 18,978 | $738.24K | Q4 2025 | Aug 11, 2026 |
| Hsbc Holdings Plc | Buy | +19,486 | — | 19,486 | $760.34K | Q4 2025 | Mar 06, 2026 |
| Sunbelt Securities, Inc. | Buy | +1 | — | 1 | $39.00 | Q4 2025 | Feb 20, 2026 |
| Mackenzie Financial Corp | Buy | +37,317 | — | 37,317 | $1.46M | Q4 2025 | Feb 18, 2026 |
| Summit Global Investments | Buy | +12,365 | — | 12,365 | $481.00K | Q4 2025 | Feb 18, 2026 |
| Raymond James Financial Inc | Buy | +5,238 | — | 5,238 | $203.76K | Q4 2025 | Feb 18, 2026 |
| Rtw Investments, Lp | Buy | +2,115,237 | — | 2,115,237 | $82.28M | Q4 2025 | Feb 17, 2026 |
| Portolan Capital Management, Llc | Buy | +1,729,463 | — | 1,729,463 | $67.28M | Q4 2025 | Feb 17, 2026 |
| Summit Partners Public Asset Management, Llc | Buy | +1,058,725 | — | 1,058,725 | $41.18M | Q4 2025 | Feb 17, 2026 |
| Palisade Capital Management, Lp | Buy | +567,777 | — | 567,777 | $22.09M | Q4 2025 | Feb 17, 2026 |
| Citadel Advisors Llc | Buy | +366,356 | — | 366,356 | $14.25M | Q4 2025 | Feb 17, 2026 |
| Millennium Management Llc | Buy | +308,914 | — | 308,914 | $12.02M | Q4 2025 | Feb 17, 2026 |
| Bank Of America Corp | Buy | +263,019 | — | 263,019 | $10.23M | Q4 2025 | Feb 17, 2026 |
| Northern Trust Corp | Buy | +262,243 | — | 262,243 | $10.20M | Q4 2025 | Feb 17, 2026 |
| Bridgeway Capital Management, Llc | Buy | +246,920 | — | 246,920 | $9.61M | Q4 2025 | Feb 17, 2026 |
| Qube Research & Technologies Ltd | Buy | +235,518 | — | 235,518 | $9.16M | Q4 2025 | Feb 17, 2026 |
| Wellington Management Group Llp | Buy | +218,560 | — | 218,560 | $8.50M | Q4 2025 | Feb 17, 2026 |
| Silvercrest Asset Management Group Llc | Buy | +205,002 | — | 205,002 | $7.97M | Q4 2025 | Feb 17, 2026 |
| Braidwell Lp | Buy | +177,183 | — | 177,183 | $6.89M | Q4 2025 | Feb 17, 2026 |
| Tudor Investment Corp Et Al | Buy | +167,178 | — | 167,178 | $6.50M | Q4 2025 | Feb 17, 2026 |
| D. E. Shaw & Co., Inc. | Buy | +159,709 | — | 159,709 | $6.21M | Q4 2025 | Feb 17, 2026 |
| Parkman Healthcare Partners Llc | Buy | +150,558 | — | 150,558 | $5.86M | Q4 2025 | Feb 17, 2026 |
| Point72 Asset Management, L.P. | Buy | +119,458 | — | 119,458 | $4.65M | Q4 2025 | Feb 17, 2026 |
| Two Sigma Investments, Lp | Buy | +84,066 | — | 84,066 | $3.27M | Q4 2025 | Feb 17, 2026 |
| Trexquant Investment Lp | Buy | +64,605 | — | 64,605 | $2.51M | Q4 2025 | Feb 17, 2026 |
| Aqr Capital Management Llc | Buy | +63,881 | — | 63,881 | $2.48M | Q4 2025 | Feb 17, 2026 |
| Fmr Llc | Buy | +42,286 | — | 42,286 | $1.64M | Q4 2025 | Feb 17, 2026 |
| Osaic Holdings, Inc. | Buy | +36,404 | — | 36,404 | $1.42M | Q4 2025 | Feb 17, 2026 |
| Ameriprise Financial Inc | Buy | +35,368 | — | 35,368 | $1.38M | Q4 2025 | Feb 17, 2026 |
| Price T Rowe Associates Inc | Buy | +34,138 | — | 34,138 | $1.33M | Q4 2025 | Feb 17, 2026 |
Frequently asked questions about CSTL activity
Which institutional owners are buying CSTL?
Institutional owners buying CSTL include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.
What does "buy" mean in CSTL activity?
"Buy" means an investor increased their reported position in CSTL compared to the prior reporting period. This reflects growing exposure to CASTLE BIOSCIENCES INC (CSTL) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).
Is institutional interest in CSTL increasing?
Institutional interest in CSTL can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.
Related CSTL Institutional Insights
- CSTL Overview
- CSTL 13F Institutional Holders
- CSTL Superinvestors
- Healthcare Sector Institutional Ownership
- Healthcare Sector Portfolio Overlap
- Institutional Portfolio Overlap & Shared Holdings
- Most Bought Healthcare Stocks By Institutional Investors
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- CSTL Insider Trading & SEC Form 4 Activity
- CSTL Articles
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