Castle Biosciences (NASDAQ: CSTL) CFO awarded 8,124 PSUs, stock units

Rhea-AI Filing Summary

Castle Biosciences Chief Financial Officer Frank Stokes reported equity awards tied to performance-based stock units. On 01/12/2026, 8,124 Performance-Based Stock Units (PSUs) granted on March 4, 2024 vested after the board certified that certain performance criteria were met, resulting in the acquisition of 8,124 shares of common stock at a price of $0 per share.

These vested PSUs represent 50% of the 2024 PSU grant. The remaining 50% of the 2024 PSUs, representing an additional 8,124 PSUs, will vest only if specified milestones are achieved. Following the transaction, Stokes beneficially owns 58,450 shares of common stock directly and 8,124 PSUs.

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^*

Stokes Frank

(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 Financial 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		8,124(1)	A	$0	58,450	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
Performance-Based Stock Unit	(2)	01/12/2026		A		8,124		(2)	(2)	Common Stock	8,124	$0	8,124	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. 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 CSTL disclose in this Form 4?

The filing shows that Chief Financial Officer Frank Stokes acquired 8,124 shares of Castle Biosciences common stock on 01/12/2026 at a price of $0 per share, upon the vesting of performance-based stock units.

How many performance-based stock units did the Castle Biosciences CFO have vest?

The filing states that 8,124 Performance-Based Stock Units (PSUs) from the March 4, 2024 grant vested after the board certified that certain performance criteria were satisfied on January 12, 2026.

How many Castle Biosciences shares does the CFO own after this transaction?

After the reported transaction, the CFO beneficially owns 58,450 shares of Castle Biosciences common stock directly, along with 8,124 PSUs that remain outstanding.

What portion of the 2024 PSUs for CSTL’s CFO has vested so far?

The filing explains that the 8,124 vested PSUs represent 50% of the Performance-Based Stock Units granted on March 4, 2024, referred to as the 2024 PSUs.

What remains unvested from the 2024 performance-based stock unit grant at Castle Biosciences?

The document notes that the remaining 50% of the 2024 PSUs, representing 8,124 PSUs, will vest in the future only if certain milestones are achieved.

How is each performance-based stock unit described in the CSTL Form 4?

According to the filing, each PSU represents the right to receive one share of Castle Biosciences common stock, subject to the satisfaction of the specified performance milestones.