Castle Biosciences Ownership & Insider Activity

Castle Biosciences (CSTL) institutional and insider ownership, recent insider transactions and ownership breakdown.

Insiders own 2.0% of shares outstanding. Institutional investors hold 54.5%. Over the past 90 days, insiders made 18 sales worth $8.1M.

Shares Outstanding

30.550M

Shares Float

29.834M

Insider Shares Owned

600.910K

Insider % Owned

2.0%

Institutional Shares Held

16.654M

Institutional % Held

54.5%

Ownership Breakdown

Net Insider Activity by Month

Purchases (90d)

Sales (90d)

$8.1M total

Net Activity

Net Selling

Net Value (90d)

-$8.1M

Castle Biosciences Insider Transactions (Last 6 Months)

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Date	Insider	Title	Type	Shares	Price	Value
Oct 19, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	14.496K	$31.91	$463K
Oct 12, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	3.288K	$33.64	$111K
Oct 5, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	6.331K	$18.98	$496K
Oct 1, 2026	Kristen Oelschlager	CHIEF OPERATING OFFICER	SELL-OPTIONS	—	$19.67	$135K
Sep 29, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	6.577K	$35.29	$232K
Sep 21, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	5.916K	$18.86	$492K
Sep 14, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	6.600K	$33.73	$223K
Sep 11, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	5.934K	$17.21	$444K
Sep 1, 2026	Kristen Oelschlager	CHIEF OPERATING OFFICER	SELL-OPTIONS	—	$18.39	$125K
Aug 31, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	1.730K	$32.81	$57K
Aug 28, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	6.132K	$17.79	$586K
Aug 25, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	9.050K	$35.04	$317K
Aug 24, 2026	Kristen Oelschlager	CHIEF OPERATING OFFICER	SELL	24.602K	$34.06	$838K
Aug 17, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	1.730K	$29.59	$51K
Aug 14, 2026	Frank Stokes	CHIEF FINANCIAL OFFICER	SELL	24.908K	$29.77	$742K
Aug 14, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	6.132K	$16.20	$214K
Aug 4, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	16.114K	$16.73	$1.2M
Aug 3, 2026	Kristen Oelschlager	CHIEF OPERATING OFFICER	SELL	8.586K	$29.77	$256K
Jul 31, 2026	Tobin Juvenal	CHIEF COMMERCIAL OFFICER	SELL	19.040K	$29.21	$556K
Jul 31, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	11.502K	$16.34	$826K
Jul 27, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$13.28	$223K
Jul 14, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$12.65	$94K
Jul 1, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$13.34	$224K
Jul 1, 2026	Kristen Oelschlager	CHIEF OPERATING OFFICER	SELL	8.586K	$24.42	$210K
Jun 16, 2026	Kristen Oelschlager	CHIEF OPERATING OFFICER	SELL	8.587K	$20.71	$178K
Jun 15, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$11.52	$85K
Jun 1, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$11.62	$190K
May 20, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$11.27	$83K
May 7, 2026	DEREK MAETZOLD	PRES. & CHIEF EXEC. OFFICER	SELL	3.622K	$12.27	$203K

Congressional Trading Activity

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Date	Member	Party	Chamber	Action	Amount
Mar 15, 2022	Josh Gottheimer	D	House	Sale	$1,001 - $15,000

Castle Biosciences Inc