Castle Biosciences (CSTL) COO reports 9,207 PSU and stock grant award

Rhea-AI Filing Summary

Castle Biosciences Chief Operating Officer Kristen M. Oelschlager reported equity awards tied to performance. On January 12, 2026, she received 9,207 Performance-Based Stock Units (PSUs), each representing the right to one share of common stock at a price of $0. On the same date, 9,207 shares of common stock were acquired at $0 upon vesting of 50% of PSUs granted on March 4, 2024, after the board certified that performance criteria were met.

Following these transactions, she directly holds 21,530 shares of Castle Biosciences common stock and indirectly holds 97,251 shares through The Fritz Shorter Trust, where she and her spouse are trustees and beneficiaries. The reported PSUs represent the remaining 50% of the 2024 performance-based grant, which will vest only if additional milestones are achieved.

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

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

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)
01/12/2026

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	01/12/2026		A		9,207(1)	A	$0	21,530	D
Common Stock								97,251	I	The Fritz Shorter Trust(2)

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
Performance-Based Stock Unit	(3)	01/12/2026		A		9,207		(3)	(3)	Common Stock	9,207	$0	9,207	D

Explanation of Responses:

1. Represents 50% of the Performance-Based Stock Units ("PSUs") granted on March 4, 2024 ("2024 PSUs") that vested based on the satisfaction of certain performance criteria as certified by the board of directors of the Issuer on January 12, 2026.

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

3. Each PSU represents the right to receive one share of the Issuer's Common Stock. These PSUs represent the remaining 50% of the 2024 PSUs which will vest subject to the achievement of certain milestones.

	/s/ Frank Stokes, Attorney-in-Fact	01/14/2026
	** 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).
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FAQ

What insider transaction did Castle Biosciences (CSTL) report for its COO?

Castle Biosciences reported that Chief Operating Officer Kristen M. Oelschlager received 9,207 Performance-Based Stock Units and 9,207 shares of common stock on January 12, 2026, both at a price of $0.

What are the 2024 performance-based stock units mentioned in the CSTL Form 4?

The filing explains that the 9,207 shares of common stock represent 50% of the 2024 Performance-Based Stock Units granted on March 4, 2024, which vested after the board certified that certain performance criteria were satisfied on January 12, 2026.

How many Castle Biosciences shares does the COO own after this Form 4 transaction?

After the reported transactions, the COO directly owns 21,530 shares of Castle Biosciences common stock and indirectly owns 97,251 shares through The Fritz Shorter Trust.

What is The Fritz Shorter Trust referenced in the CSTL insider filing?

The filing states that 97,251 common shares are held by The Fritz Shorter Trust, of which the reporting person and her spouse are the trustees and beneficiaries, and these shares are reported as indirect ownership.

Do the reported PSUs in the CSTL Form 4 automatically convert to shares?

Each Performance-Based Stock Unit (PSU) represents the right to receive one share of Castle Biosciences common stock. The filing notes that the reported PSUs are the remaining 50% of the 2024 PSUs and will vest only upon achievement of specified milestones.

Was there any cash paid for the Castle Biosciences equity reported in this Form 4?

No cash was paid for the reported awards. Both the 9,207 common shares and the 9,207 PSUs are shown with a transaction price of $0, indicating they were granted or vested as equity compensation.