CASTLE BIOSCIENCES INC (CSTL) Stock Institutional Trading Activity


CASTLE BIOSCIENCES INC (CSTL) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Renaissance Technologies LLC and ARK Invest. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q1 2020Renaissance Technologies LLCBuy33,20033,200$990
Q4 2019ARK InvestBuy39,927206,014$7,081
Q3 2019ARK InvestBuy166,087166,087$3,005

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.