Frank Stokes - 05 Mar 2026 Form 4 Insider Report for CASTLE BIOSCIENCES INC (CSTL)

Role: Chief Financial Officer
Signature: /s/ Frank Stokes, Attorney-in-fact
Issuer symbol: CSTL
Transactions as of: 05 Mar 2026
Net transactions value: -$167,908
Form type: 4
Filing time: 09 Mar 2026, 16:13:53 UTC
Previous filing: 05 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Stokes Frank	Chief Financial Officer	C/O CASTLE BIOSCIENCES, INC., 1500 W. PARKWOOD AVE SUITE 400, FRIENDSWOOD	/s/ Frank Stokes, Attorney-in-fact	09 Mar 2026	0001782815

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	CSTL	Common Stock	Sale	$167,908	-6,001	-9.1%	$27.98	60,085	05 Mar 2026	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

Transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Explanation of Responses:

Id	Content
F1	The transaction on this Form 4 was made pursuant to a Rule 10b5-1 plan adopted by Frank Stokes on November 13, 2025.
F2	This transaction was executed in multiple trades at prices ranging from $27.51 to $28.41, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Content

The transaction on this Form 4 was made pursuant to a Rule 10b5-1 plan adopted by Frank Stokes on November 13, 2025.

This transaction was executed in multiple trades at prices ranging from $27.51 to $28.41, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.