[Form 4] CASTLE BIOSCIENCES INC Insider Trading Activity

Rhea-AI Filing Summary

Castle Biosciences (CSTL) reported an insider transaction by its Chief Operating Officer. On November 11, 2025, the COO sold 18,932 shares of common stock (code S) under a Rule 10b5-1 plan adopted on March 6, 2025 at a $35.10 weighted-average price, with trade prices ranging from $35.00 to $35.37.

Following the transactions, the reporting person beneficially owns 12,323 shares directly and 97,251 shares indirectly via The Fritz Shorter Trust. The filing also notes a transfer of 3,686 shares from the trust to direct holdings on November 11, 2025.

Insights

Governance & Insider Transactions Analyst

Planned insider sale; routine disclosure with unchanged thesis.

The transaction is a Form 4 insider sale by the COO executed under a Rule 10b5-1 trading plan adopted on March 6, 2025. The reported sale was 18,932 shares at a weighted-average price of $35.10, with individual trades ranging from $35.00 to $35.37.

Post-transaction holdings remain meaningful: 12,323 shares directly and 97,251 shares indirectly via The Fritz Shorter Trust. The filing also records a same-day transfer of 3,686 shares from the trust to direct ownership. Overall, this is a standard, pre-planned transaction disclosure; actual impact depends on broader ownership and trading patterns.

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)
11/11/2025

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	11/11/2025		S(1)		18,932	D	$35.1(2)	12,323(3)	D
Common Stock								97,251(3)	I	The Fritz Shorter Trust(4)

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 $35.00 to $35.37, 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. On November 11, 2025, the Reporting Person transferred 3,686 shares from the Fritz Shorter Trust to their direct holdings.

4. 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	11/13/2025
	** 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

How many CSTL shares did the COO sell?

The COO sold 18,932 shares of Castle Biosciences common stock.

What price did the COO receive for the CSTL shares?

The sale was executed at a $35.10 weighted-average price, with trades ranging from $35.00 to $35.37.

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

Yes. The transactions were made pursuant to a Rule 10b5-1 plan adopted on March 6, 2025.

What are the COO’s holdings after the transaction?

Post-transaction, holdings are 12,323 shares directly and 97,251 shares indirectly via The Fritz Shorter Trust.

Did the filing report any share transfers between accounts?

Yes. On November 11, 2025, 3,686 shares were transferred from The Fritz Shorter Trust to direct holdings.

What is the reporting person’s role at Castle Biosciences (CSTL)?

The reporting person is the company’s Chief Operating Officer.