CASTLE BIOSCIENCES INC (CSTL) is held by 107 institutional investors that disclose positions via SEC 13F filings. The largest disclosed holder is BlackRock, Inc. as of Q1 2026.

Are institutions buying or selling CSTL?

In Q1 2026, 61 institutions opened or increased positions in CASTLE BIOSCIENCES INC while 54 reduced or exited — a net buying quarter.

What is the Smart Money Verdict on CSTL?

The Smart Money Verdict combines four independent sources (institutional 13F activity, insider trades, activist filings, and congressional trades) into a single assessment for CASTLE BIOSCIENCES INC.

How many hedge funds hold CSTL?

107 institutional investors report holding CASTLE BIOSCIENCES INC (CSTL) as of Q1 2026, based on SEC 13F filings.

Is institutional money flowing into CSTL?

As of Q1 2026, tracked institutions in CASTLE BIOSCIENCES INC show 61 buyers versus 54 sellers — net inflows.

CASTLE BIOSCIENCES INC

CSTL·14843C105·US·Common Stock·Healthcare - Diagnostics & Research-13D/G

107

Holders

Avg rating(23 Elite)

$527M

Total Value

53% (122)

Fund Consensus

61 buying - 54 selling

Smart Money Verdict

View all

Held by 107 funds

23 elite

Who's Trading

ActivistPOPortolan Capital Management, LLC4.5%May 15, 2026

Activist

RTW Investments, LP9.3%May 15, 2026

InsiderMJMAETZOLD DEREK JSell $26KMay 7, 2026

InsiderMJMAETZOLD DEREK JSell $4KMay 7, 2026

InsiderMJMAETZOLD DEREK JSell $22KMay 7, 2026

InsiderMJMAETZOLD DEREK JSell $4KMay 7, 2026

InsiderMJMAETZOLD DEREK JExercise 6K shMay 7, 2026

InsiderMJMAETZOLD DEREK JSell $117KMay 7, 2026

InsiderMJMAETZOLD DEREK JSell $20KMay 7, 2026

InsiderMJMAETZOLD DEREK JSell $5KMay 7, 2026

View all insider trades View all activist filings

13F: Mar 31, 2026Insider & Congress: Updated regularly

Fund	Action	Shares	Value	Weight	Est. P&L	Conviction
BlackRock, Inc.	Decreased	3M(-3.9%)	$73.2M	0.0%	-9.27%	0
RTW INVESTMENTS, LP	Increased	2.8M(+30.4%)	$67.7M	0.7%	-35.14%	53
PRINCIPAL FINANCIAL GROUP INC	Decreased	1.8M(-2.1%)	$43.5M	0.0%	-7.61%	0
VAVANGUARD CAPITAL MANAGEMENT LLC	New	1.2M	$28.9M	0.0%	-13.96%	40
DIMENSIONAL FUND ADVISORS LP	Decreased	1M(-9.1%)	$25.5M	0.0%	+7.97%	0
VPVANGUARD PORTFOLIO MANAGEMENT LLC	New	861,771	$21.2M	0.0%	-13.96%	39
Allianz Asset Management GmbH	Increased	811,324(+30.4%)	$19.9M	0.0%	-1.86%	36
STATE STREET CORP	Increased	769,079(+4.4%)	$18.9M	0.0%	+3.86%	30
GEODE CAPITAL MANAGEMENT, LLC	Increased	728,100(+1.8%)	$17.9M	0.0%	-37.20%	29
Qube Research & Technologies Ltd	Increased	559,583(+137.6%)	$13.7M	0.0%	-11.73%	45
RENAISSANCE TECHNOLOGIES LLC	Increased	532,800(+8.1%)	$13.1M	0.0%	-2.60%	30
Nuveen, LLC	Decreased	522,127(-0.5%)	$12.8M	0.0%	+18.05%	0
WASATCH ADVISORS LP	Decreased	455,036(-15.3%)	$11.2M	0.1%	-36.93%	0
MORGAN STANLEY	Increased	428,934(+110.7%)	$10.5M	0.0%	-7.31%	45
Connor, Clark & Lunn Investment Management Ltd.	Decreased	377,082(-2.9%)	$9.3M	0.0%	-6.18%	0
MILLENNIUM MANAGEMENT LLC	Increased	353,319(+14.4%)	$8.7M	0.0%	-2.29%	31
GOLDMAN SACHS GROUP INC	Increased	341,171(+18.8%)	$8.4M	0.0%	-3.35%	32
SCHRODER INVESTMENT MANAGEMENT GROUP	Decreased	298,941(-39.3%)	$7M	0.0%	+18.76%	0
NORTHERN TRUST CORP	Increased	273,101(+4.1%)	$6.7M	0.0%	-34.49%	28
SILVERCREST ASSET MANAGEMENT GROUP LLC	Increased	268,535(+31.0%)	$6.6M	0.0%	-7.06%	35