Castle Biosciences Inc (CSTL) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

27,191,111Shares Outstanding

54,082Shares held by institutions

$1,807,420Value of institutional holdings

99.02%Institutional ownership %

5.09%Shares Changed QoQ

185No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

Castle Biosciences Inc (NASDAQ:CSTL) currently has 185 active institutional owners and shareholders as of today (December 2025), that have filed 13F forms with the Securities Exchange Commission (SEC).

Institutional ownership in Castle Biosciences edged up to 99.0% in December 2025, compared to 98.1% in September 2025.
Quarterly data indicates a 5.09% shift in institutional share volume, and the annual owner count reflects a decrease of 4.64%.
Of these 185 institutional investors, 100 increased their holdings in Castle Biosciences, while 66 of them reduced positions, and 19 investors maintained their exposure.
This class of investors increased its holdings in Castle Biosciences to 26.92Mn shares for the 13F-cycle ending December 2025, up by 1.30Mn shares quarter on quarter, and up 641.83K shares year over year.
BlackRock, Inc. continues to be the largest institutional holder of Castle Biosciences as of December 31, 2025, with a position of 3.11Mn shares, representing 11.42% of the company's outstanding stock.
Among the most significant buyers of Castle Biosciences during December 2025 were RTW INVESTMENTS, LP (2.12Mn), SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC (658.73K), EVENTIDE ASSET MANAGEMENT, LLC (305.00K), WELLINGTON MANAGEMENT GROUP LLP (218.56K), Portolan Capital Management, LLC (214.35K).
Leading sellers of Castle Biosciences stock in December 2025 included BRAIDWELL LP (645.55K), Nuveen, LLC (432.40K), DIMENSIONAL FUND ADVISORS LP (330.29K), MILLENNIUM MANAGEMENT LLC (266.18K), AMERIPRISE FINANCIAL INC (220.87K).
The top 10 institutional holders of Castle Biosciences for the quarter ending December 2025 included BlackRock, Inc. (3.11Mn), VANGUARD GROUP INC (2.20Mn), RTW INVESTMENTS, LP (2.12Mn), PRINCIPAL FINANCIAL GROUP INC (1.81Mn), Portolan Capital Management, LLC (1.73Mn), DIMENSIONAL FUND ADVISORS LP (1.14Mn), SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC (1.06Mn), STATE STREET CORP (736.45K), GEODE CAPITAL MANAGEMENT, LLC (714.91K), AIGH Capital Management LLC (624.72K).

185 Institutional Holders

54,082 Total Shares Held

Rows:

Download Data

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
BlackRock, Inc.	31 Dec, 2025	3,105,246	-84,650	-2.65%	$120,794,069.00
VANGUARD GROUP INC	31 Dec, 2025	2,199,829	27,511	1.27%	$85,573,349.00
RTW INVESTMENTS, LP	31 Dec, 2025	2,115,237	2,115,237	0.00%	$82,282,719.00
PRINCIPAL FINANCIAL GROUP INC	31 Dec, 2025	1,807,644	13,289	0.74%	$70,317,352.00
Portolan Capital Management, LLC	31 Dec, 2025	1,729,463	214,352	14.15%	$67,276,111.00
DIMENSIONAL FUND ADVISORS LP	31 Dec, 2025	1,143,799	-330,290	-22.41%	$44,494,673.00
SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC	31 Dec, 2025	1,058,725	658,725	164.68%	$41,184,403.00
STATE STREET CORP	31 Dec, 2025	736,454	12,374	1.71%	$28,648,061.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	714,913	16,303	2.33%	$27,814,871.00
AIGH Capital Management LLC	31 Dec, 2025	624,719	-82,568	-11.67%	$24,301,569.00
Allianz Asset Management GmbH	31 Dec, 2025	622,299	-26,052	-4.02%	$24,207,431.00
PALISADE CAPITAL MANAGEMENT, LP	31 Dec, 2025	567,777	-70,879	-11.10%	$22,086,525.00
WASATCH ADVISORS LP	31 Dec, 2025	537,241	-131,879	-19.71%	$20,898,675.00
Nuveen, LLC	31 Dec, 2025	524,681	-432,400	-45.18%	$20,410,091.00
RENAISSANCE TECHNOLOGIES LLC	31 Dec, 2025	493,100	-69,500	-12.35%	$19,181,590.00
SCHRODER INVESTMENT MANAGEMENT GROUP	31 Dec, 2025	492,161	-2,789	-0.56%	$19,346,849.00
ACADIAN ASSET MANAGEMENT LLC	31 Dec, 2025	390,406	-61,246	-13.56%	$15,180.00
Connor, Clark & Lunn Investment Management Ltd.	31 Dec, 2025	388,491	52,600	15.66%	$15,112,300.00
CITADEL ADVISORS LLC	31 Dec, 2025	366,356	115,441	46.01%	$14,251,249.00
MILLENNIUM MANAGEMENT LLC	31 Dec, 2025	308,914	-266,175	-46.28%	$12,016,755.00

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