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 21 sales; 176 institutions reported holding it in 13F filings for Q2 2026, worth $653.8M in total; no superinvestor holds it.

Q2 2026 vs. Q1 2026

How the institutions holding Castle Biosciences Inc changed between Q1 2026 and Q2 2026.

All holders in Q2 2026 All holders in Q1 2026

13F holders of CSTL: Q1 2026 compared with Q2 2026
Measure	Q1 2026	Of which not filed for Q2 2026	Q2 2026	Change
Holders	186	3	176	−7
Shares	27.6M	18.1K	27.4M	−182.5K (−0.7%)
Value	$677.8M	$443.1K	$653.8M	−$23.5M (−3.5%)

3 institutions that held it in Q1 2026 haven't filed for Q2 2026 yet. Not filing isn't selling, so the changes leave them out.

New holders (23)

Institutions that held Castle Biosciences Inc at the end of Q2 2026 but not at the end of Q1 2026.

Institutions new to CSTL in Q2 2026
Institution	Shares	Value	% of portfolio
Jefferies Financial Group Inc.	647,391	$15.4M	0.14%
Point72 Asset Management, L.P.	357,317	$8.52M	0.01%
Kennedy Capital Management, Inc.	348,371	$8.31M	0.15%
First Trust Advisors LP	145,064	$3.46M	0.00%
Norges Bank	60,100	$1.43M	0.00%
Toroso Investments, LLC	22,186	$529.1K	0.00%
Counterpoint Mutual Funds LLC	16,510	$393.8K	0.04%
Diversify Advisory Services, LLC	15,932	$389.4K	0.01%
Jupiter Topco LLC	15,037	$358.2K	0.00%
Quadrature Capital Ltd	10,175	$242.7K	0.00%
Allstate Corp	9,642	$230.0K	0.00%
EntryPoint Capital, LLC	8,942	$213.3K	0.05%
Intech Investment Management LLC	8,580	$204.6K	0.00%
Global Retirement Partners, LLC	1,100	$26.2K	0.00%
GWM Advisors LLC	842	$20.1K	0.00%
Nykredit A/S	597	$14.2K	0.00%
National Bank of Canada	191	$4.55K	0.00%
Optiver Holding B.V.	174	$4.15K	0.00%
Silver Grove Financial Group, Inc.	156	$3.72K	0.00%
Clearstead Advisors, LLC	48	$1.15K	0.00%
Caitong International Asset Management Co., Ltd	6	$143	0.00%
Fortitude Family Office, LLC	1	$24	0.00%
Freestone Grove Partners LP	1	$24	0.00%

Sold out (30)

Institutions that held Castle Biosciences Inc at the end of Q1 2026 and filed for Q2 2026 without it.

Institutions that sold out of CSTL in Q2 2026
Institution	Shares, Q1 2026	Value, Q1 2026
Eventide Asset Management, LLC	386,425	$9.49M
Schroder Investment Management Group	298,941	$7.04M
SG Americas Securities, LLC	244,886	$6.01M
Formula Growth Ltd	46,000	$1.13M
Nomura Holdings Inc	35,748	$877.6K
ExodusPoint Capital Management, LP	32,608	$800.5K
CI Private Wealth, LLC	31,870	$782.4K
Fox Run Management, L.L.C.	26,247	$618.1K
Magnetar Financial LLC	23,332	$572.8K
Brevan Howard Capital Management LP	18,560	$455.6K
Dynamic Technology Lab Private Ltd	15,913	$390.7K
Jump Financial, LLC	12,300	$302.0K
Gsa Capital Partners LLP	12,236	$300.0K
Canada Pension Plan Investment Board	11,400	$279.9K
Jackson Creek Investment Advisors LLC	11,214	$275.0K
Graham Capital Management, L.P.	11,133	$273.3K
Susquehanna International Group, LLP	9,520	$233.7K
Globeflex Capital L P	3,759	$92.3K
Quadrant Capital Group LLC	336	$8.25K
Group One Trading, L.P.	292	$7.17K
Advisory Services Network, LLC	287	$7.05K
Massmutual Trust Co FSB	202	$4.96K
RWM Asset Management, LLC	88	$2.16K
Signaturefd, LLC	45	$1.10K
MAI Capital Management	19	$467
Missouri Trust & Investment Co	19	$466
Signature Equity Partners, LLC	16	$393
Wealth Preservation Advisors, LLC	4	$98
Larson Financial Group LLC	1	$25
Twin Peaks Wealth Advisors, LLC	1	$25

Not filed for Q2 2026 yet (3)

Institutions that held Castle Biosciences Inc at the end of Q1 2026 and haven't filed a 13F for Q2 2026. Not filing isn't selling, so they aren't counted as sold out.

Institutions holding CSTL in Q1 2026 that haven't filed for Q2 2026
Institution	Shares, Q1 2026	Value, Q1 2026
Janus Henderson Group PLC	15,037	$369.1K
CWM, LLC	3,010	$73.9K
Sunbelt Securities, Inc.	3	$74