Castle Biosciences (CSTL) CFO sells 6,001 shares under 10b5-1 plan

Rhea-AI Filing Summary

Castle Biosciences Chief Financial Officer Frank Stokes sold 6,001 shares of common stock on March 5, 2026 in an open-market transaction at a weighted-average price of $27.98 per share. The sale was made under a prearranged Rule 10b5-1 trading plan adopted on November 13, 2025.

The transaction was executed in multiple trades at prices ranging from $27.51 to $28.41 per share, with the reported price reflecting the weighted average. After this planned sale, Stokes continues to directly own 60,085 shares of Castle Biosciences common stock.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a 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). See Instruction 10.

1. Name and Address of Reporting Person^*

Stokes Frank

(Last) (First) (Middle)

C/O CASTLE BIOSCIENCES, INC.

1500 W. PARKWOOD AVE SUITE 400

(Street)

FRIENDSWOOD TX 77546

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
CASTLE BIOSCIENCES INC [ CSTL ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/05/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/05/2026		S(1)		6,001	D	$27.98(2)	60,085	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

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

2. 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.

Remarks:

	/s/ Frank Stokes, Attorney-in-fact	03/09/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did CSTL CFO Frank Stokes report on this Form 4?

CSTL Chief Financial Officer Frank Stokes reported selling 6,001 shares of Castle Biosciences common stock. The shares were sold in an open-market transaction at a weighted-average price of $27.98 per share on March 5, 2026 under a Rule 10b5-1 plan.

At what prices did CSTL CFO Frank Stokes sell his Castle Biosciences shares?

The 6,001 Castle Biosciences shares were sold at prices ranging from $27.51 to $28.41 per share. The Form 4 reports a weighted-average sale price of $27.98 per share for the transaction carried out on March 5, 2026.

Does CSTL CFO Frank Stokes still hold Castle Biosciences shares after this sale?

Yes. After selling 6,001 shares, CSTL CFO Frank Stokes continues to directly own 60,085 shares of Castle Biosciences common stock. This remaining stake is reported as his direct ownership following the March 5, 2026 open-market sale.

Was the CSTL CFO’s March 2026 stock sale part of a prearranged trading plan?

Yes. The Form 4 states the transaction was made under a Rule 10b5-1 trading plan adopted by CSTL CFO Frank Stokes on November 13, 2025. Such plans prearrange trades to help separate personal decisions from nonpublic information.

How many CSTL insider sell transactions are reported in this Form 4 filing?

The Form 4 for CSTL reports a single insider sale transaction by CFO Frank Stokes. It covers the open-market sale of 6,001 shares of Castle Biosciences common stock on March 5, 2026, executed in multiple trades within a specified price range.