Castle Biosciences insider sale: 12,678 shares at $25.04 avg

Rhea-AI Filing Summary

Castle Biosciences (CSTL) disclosed that its Chief Operating Officer reported an open-market sale of 12,678 shares of common stock on 10/31/2025 at a weighted-average price of $25.04, executed in multiple trades within a $25.00–$25.12 range. The sale was made pursuant to a Rule 10b5-1 plan adopted on March 6, 2025.

Following the transaction, the reporting person beneficially owns 27,569 shares directly and 100,937 shares indirectly through The Fritz Shorter Trust.

Insights

Insider trading & compliance analyst

Planned 10b5-1 sale; modest size with holdings remaining.

The COO reported selling 12,678 shares of CSTL at a weighted-average of $25.04 on 10/31/2025. The filing states the trades were executed under a Rule 10b5-1 plan adopted on March 6, 2025, indicating pre-arranged instructions rather than discretionary timing.

After the sale, reported beneficial ownership is 27,569 shares direct and 100,937 shares indirect via The Fritz Shorter Trust. The filing lists a trade range of $25.00 to $25.12. Actual market impact depends on overall liquidity and future insider activity; the filing does not state further transactions.

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^*

Oelschlager Kristen M

(Last) (First) (Middle)

C/O CASTLE BIOSCIENCES, INC.

505 S FRIENDSWOOD DRIVE, SUITE 401

(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 Operating Officer

3. Date of Earliest Transaction (Month/Day/Year)
10/31/2025

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	10/31/2025		S(1)		12,678	D	$25.04(2)	27,569	D
Common Stock								100,937	I	The Fritz Shorter Trust(3)

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. These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 6, 2025

2. This transaction was executed in multiple trades at prices ranging from $25.00 to 25.12, 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.

3. Held by the Fritz Shorter Trust of which the Reporting Person and her spouse are the trustees and beneficiaries.

Remarks:

	/s/ Frank Stokes, Attorney-in-fact	11/04/2025
	** 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 did CSTL's COO report on the Form 4?

A sale of 12,678 shares of Castle Biosciences common stock on 10/31/2025.

At what price were the CSTL shares sold?

At a weighted-average price of $25.04, with individual trades from $25.00 to $25.12.

Was the sale under a Rule 10b5-1 plan?

Yes. It was made pursuant to a Rule 10b5-1 plan adopted on March 6, 2025.

How many CSTL shares does the reporting person own after the sale?

27,569 shares directly and 100,937 shares indirectly.

How is the indirect ownership held?

Through The Fritz Shorter Trust, for which the reporting person and spouse are trustees and beneficiaries.

What is the company and ticker involved?

Castle Biosciences, Inc. with ticker CSTL.