Castle Biosciences (NASDAQ: CSTL) CCO sells 20,863 pre-planned shares

Rhea-AI Filing Summary

CASTLE BIOSCIENCES INC Chief Commercial Officer Juvenal Tobin reported an open-market sale of 20,863 shares of common stock. The shares were sold at a weighted-average price of $25.24 per share, with individual trade prices ranging from $24.90 to $25.70. After this transaction, Tobin directly holds 86,825 shares. The sale was made under a pre-arranged Rule 10b5-1 trading plan adopted on December 10, 2025, indicating the timing was set in advance rather than decided opportunistically.

Insider Trade Summary 10b5-1

Net Seller: 20,863 shares ($526,582)

Net Sell 1 txn

Insider Juvenal Tobin W

Role Chief Commercial Officer

Sold 20,863 shs ($527K)

Type	Security	Shares	Price	Value
Sale	Common Stock	20,863	$25.24	$527K

Holdings After Transaction: Common Stock — 86,825 shares (Direct)

Footnotes (1)

1. This transaction was made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 10, 2025. This transaction was executed in multiple trades at prices ranging from $24.90 to $25.70, 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.

Form 4 Insider Transactions: What Each Field Means →

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^*

Juvenal Tobin W

(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 Commercial Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/12/2026

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	03/12/2026		S(1)		20,863	D	$25.24(2)	86,825	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. This transaction was made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 10, 2025.

2. This transaction was executed in multiple trades at prices ranging from $24.90 to $25.70, 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	03/16/2026
	** 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 disclose for Juvenal Tobin?

CASTLE BIOSCIENCES INC disclosed that Chief Commercial Officer Juvenal Tobin sold 20,863 shares of common stock in an open-market transaction at a weighted-average price of $25.24 per share, as reported in a Form 4 insider trading filing.

At what price did CSTL’s Chief Commercial Officer sell shares?

The 20,863 CSTL shares were sold at a weighted-average price of $25.24 each. Individual trades occurred within a price range from $24.90 to $25.70 per share, according to detailed execution information provided in the insider trading disclosure.

How many CSTL shares does Juvenal Tobin hold after the sale?

Following the reported transaction, Juvenal Tobin directly holds 86,825 shares of CASTLE BIOSCIENCES INC common stock. This post-transaction ownership reflects the remaining position after selling 20,863 shares in the open market under the disclosed Form 4 filing.

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

Yes. The filing states the sale was executed under a Rule 10b5-1 trading plan adopted by Juvenal Tobin on December 10, 2025. Such pre-arranged plans schedule trades in advance to provide structure around insider stock transactions.

Who is the insider involved in this CSTL Form 4 filing?

The insider is Juvenal Tobin, Chief Commercial Officer of CASTLE BIOSCIENCES INC. He is an officer but not a director or 10% owner, and the Form 4 reports his direct ownership and the recent open-market sale of company shares.

What does the CSTL Form 4 reveal about trading volume for the insider sale?

The Form 4 shows a total sale of 20,863 CSTL common shares in multiple trades. These trades were executed across a price range from $24.90 to $25.70, with the weighted-average sale price disclosed as $25.24 per share in the filing details.