Castle Biosciences Inc

CSTL

Exchange: Nasdaq
Industry: Services-Medical Laboratories
SEC CIK: 0001447362

SEC filings (opens in a new tab)

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.

Q3 2025 vs. Q2 2025

How the institutions holding Castle Biosciences Inc changed between Q2 2025 and Q3 2025.

All holders in Q3 2025 All holders in Q2 2025

13F holders of CSTL: Q2 2025 compared with Q3 2025
Measure	Q2 2025	Of which not filed for Q3 2025	Q3 2025	Change
Holders	152	1	173	+22
Shares	26.5M	1.79K	26.6M	+114.3K (+0.4%)
Value	$541.8M	$36.6K	$608.3M	+$66.6M (+12.3%)

1 institution that held it in Q2 2025 haven't filed for Q3 2025 yet. Not filing isn't selling, so the changes leave them out.

New holders (37)

Institutions that held Castle Biosciences Inc at the end of Q3 2025 but not at the end of Q2 2025.

Institutions new to CSTL in Q3 2025
Institution	Shares	Value	% of portfolio
AIGH Capital Management LLC	707,287	$16.1M	5.64%
Summit Partners Public Asset Management, LLC	400,000	$9.11M	0.30%
Point72 Asset Management, L.P.	336,958	$7.67M	0.02%
Summit Wealth Group LLC	122,494	$4.51M	0.62%
Cubist Systematic Strategies, LLC	50,304	$1.15M	0.02%
SummitTX Capital, L.P.	45,000	$1.02M	0.04%
Dynamic Technology Lab Private Ltd	29,310	$667.0K	0.11%
Campbell & CO Investment Adviser LLC	26,996	$614.7K	0.05%
Los Angeles Capital Management LLC	24,121	$549.2K	0.00%
Jane Street Group, LLC	22,884	$521.1K	0.00%
Panagora Asset Management Inc	21,398	$487.2K	0.00%
Capstone Investment Advisors, LLC	16,677	$379.7K	0.00%
Fox Run Management, L.L.C.	13,820	$314.7K	0.05%
SG Americas Securities, LLC	13,061	$297.0K	0.00%
Bailard, Inc.	11,400	$259.6K	0.01%
Magnetar Financial LLC	10,327	$235.1K	0.00%
Glenmede Investment Management, LP	10,199	$232.2K	0.00%
Atom Investors LP	9,827	$223.8K	0.02%
Green Alpha Advisors, LLC	9,538	$217.2K	0.21%
LPL Financial LLC	9,397	$214.0K	0.00%
Janus Henderson Group PLC	9,137	$208.2K	0.00%
Canada Pension Plan Investment Board	2,400	$54.6K	0.00%
Point72 (DIFC) Ltd	2,386	$54.3K	0.00%
State of Alaska, Department of Revenue	1,553	$35.0K	0.00%
Simplex Trading, LLC	1,512	$34.0K	0.00%
Group One Trading, L.P.	803	$18.3K	0.00%
SRS Capital Advisors, Inc.	574	$13.1K	0.00%
First Horizon Corp	447	$10.2K	0.00%
Quadrant Capital Group LLC	336	$7.65K	0.00%
Essential Partners LLC	123	$2.80K	0.00%
Point72 Europe (London) LLP	112	$2.56K	0.00%
Optiver Holding B.V.	40	$911	0.00%
US Bancorp	26	$592	0.00%
Clearstead Advisors, LLC	12	$274	0.00%
Advisory Services Network, LLC	7	$159	0.00%
Larson Financial Group LLC	1	$23	0.00%
True Wealth Design, LLC	1	$23	0.00%

Sold out (15)

Institutions that held Castle Biosciences Inc at the end of Q2 2025 and filed for Q3 2025 without it.

Institutions that sold out of CSTL in Q3 2025
Institution	Shares, Q2 2025	Value, Q2 2025
Wellington Management Group LLP	407,211	$8.32M
Squarepoint Ops LLC	125,719	$2.57M
Y-Intercept (Hong Kong) Ltd	78,938	$1.61M
XTX Topco Ltd	46,301	$945.5K
Nebula Research & Development LLC	44,472	$908.1K
Jump Financial, LLC	21,858	$446.3K
Advantage Alpha Capital Partners LP	16,021	$327.1K
Mount Yale Investment Advisors, LLC	8,362	$170.8K
Raymond James Financial Inc	662	$13.5K
Lazard Asset Management LLC	72	$1.00K
Bryn Mawr Trust Co	46	$939
Parkside Financial Bank & Trust	25	$511
Skopos Labs, Inc.	11	$225
Stephens Consulting, LLC	2	$41
Twin Peaks Wealth Advisors, LLC	1	$19

Not filed for Q3 2025 yet (1)

Institutions that held Castle Biosciences Inc at the end of Q2 2025 and haven't filed a 13F for Q3 2025. Not filing isn't selling, so they aren't counted as sold out.

Institutions holding CSTL in Q2 2025 that haven't filed for Q3 2025
Institution	Shares, Q2 2025	Value, Q2 2025
First Horizon Advisors, Inc.	1,792	$36.6K