Castle Biosciences Juvenal sells 5,543 shares

Both reported sales were made under a Rule 10b5-1 plan the chief commercial officer adopted on May 28, 2026.

Rhea-AI Filing Summary

Castle Biosciences (CSTL) Chief Commercial Officer Tobin W. Juvenal reported two direct sales of common stock: 5,543 shares on September 29, 2026, at a weighted-average price of $35.4980 per share, and 1,034 shares on September 30, 2026, at a weighted-average price of $34.2000 per share. Both sales were made pursuant to a Rule 10b5-1 plan adopted May 28, 2026. The September 29 trades were executed at prices ranging from $35.010 to $35.935, inclusive; the September 30 trades ranged from $34.090 to $34.525, inclusive.

Insider Trade Summary 10b5-1

Net Seller: 6,577 shares

Net Sell 2 txns

Insider Juvenal Tobin W

Role Chief Commercial Officer

Sold 6,577 shs ($232K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F3	1,034	$34.20	$35K
Sale	Common Stock F1, F2	5,543	$35.498	$197K

Holdings After Transaction: Common Stock — 52,007 shares (Direct)

Footnotes (3)

1. F1. This transaction was made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on May 28, 2026.
2. F2. This transaction was executed in multiple trades at prices ranging from $35.010 to $35.935, 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. F3. This transaction was executed in multiple trades at prices ranging from $34.090 to $34.525, 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.

Key Figures

Shares sold: 5,543 shares Weighted-average sale price: $35.4980 per share Shares sold: 1,034 shares +1 more

4 metrics

Shares sold 5,543 shares September 29, 2026

Weighted-average sale price $35.4980 per share September 29, 2026

Shares sold 1,034 shares September 30, 2026

Weighted-average sale price $34.2000 per share September 30, 2026

Key Terms

Rule 10b5-1 plan, weighted-average sale price, multiple trades

3 terms

Rule 10b5-1 plan regulatory

"made pursuant to a Rule 10b5-1 plan adopted"

A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret information.

weighted-average sale price financial

"reflects the weighted-average sale price"

multiple trades financial

"executed in multiple trades at prices ranging"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many CSTL shares did the chief commercial officer sell, and at what prices?

Tobin W. Juvenal, Castle Biosciences' chief commercial officer, sold 5,543 shares on September 29, 2026, at a weighted-average $35.4980 per share and 1,034 shares on September 30, 2026, at a weighted-average $34.2000 per share. Both sales were made under a Rule 10b5-1 plan adopted May 28, 2026.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/01/2026 - 04:21 PM Accepted by SEC EDGAR 10/01/2026 - 04:21 PM Learn about SEC filing dates

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 TEXAS 77546

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/29/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	09/29/2026		S(1)		5,543	D	$35.498(2)	53,041	D
Common Stock	09/30/2026		S(1)		1,034	D	$34.2(3)	52,007	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 May 28, 2026.

2. This transaction was executed in multiple trades at prices ranging from $35.010 to $35.935, 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. This transaction was executed in multiple trades at prices ranging from $34.090 to $34.525, 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	10/01/2026
	** 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.
* Form 4: SEC 1474 (03-26)