Castle Biosciences (CSTL) CCO sells 19,040 shares under 10b5-1 plan

Q: What insider activity did Castle Biosciences (CSTL) report for Juvenal Tobin?

Castle Biosciences reported that Chief Commercial Officer Juvenal Tobin sold 19,040 shares of CSTL common stock in four open‑market or private transactions on July 31 and August 3, 2026 , as disclosed in a Form 4 insider trading report.

Q: How many CSTL shares did Juvenal Tobin sell and on which dates?

Juvenal Tobin sold a total of 19,040 CSTL shares . He sold 17,310 shares on July 31, 2026 in three tranches and an additional 1,730 shares on August 3, 2026 , according to the reported transactions.

Q: At what prices were Juvenal Tobin’s CSTL stock sales executed?

The reported weighted‑average sale prices were $28.8420 , $29.5790 , and $30.2640 per share on July 31, 2026, and $28.2500 per share on August 3, 2026. Each reflects multiple trades aggregated into a single weighted‑average sale price.

Q: Were Juvenal Tobin’s Castle Biosciences (CSTL) sales under a Rule 10b5-1 plan?

Yes. The transactions were made pursuant to a Rule 10b5‑1 trading plan that Juvenal Tobin adopted on December 10, 2025 , and the filing’s Rule 10b5‑1 checkbox is marked as affirming plan‑based trades.

Q: What is Juvenal Tobin’s role at Castle Biosciences (CSTL)?

Juvenal Tobin is the company’s Chief Commercial Officer . The reported Form 4 transactions involve his direct ownership of Castle Biosciences common stock, with sales coded as open‑market or private transactions.

Q: How many separate transactions did the CSTL Form 4 report for Juvenal Tobin?

The Form 4 reports four non‑derivative transactions in Castle Biosciences common stock for Juvenal Tobin, all coded as “S” for sale and classified as sales in open‑market or private transactions.

Filing Impact

(Very High)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

Castle Biosciences Inc Chief Commercial Officer Juvenal Tobin reported open‑market or private sales totaling 19,040 shares of common stock in four transactions on July 31 and August 3, 2026. The shares were sold at weighted‑average prices ranging from $28.2500 to $30.2640 per share under a Rule 10b5‑1 trading plan adopted on December 10, 2025.

Insights

Analyzing...

Insider Trade Summary 10b5-1

Net Seller: 19,040 shares

Net Sell 4 txns

Insider Juvenal Tobin W

Role Chief Commercial Officer

Sold 19,040 shs ($556K)

Type	Security	Shares	Price	Value
Sale	Common Stock ^{F1, F5}	1,730	$28.25	$49K
Sale	Common Stock ^{F1, F2}	8,149	$28.842	$235K
Sale	Common Stock ^{F1, F3}	7,270	$29.579	$215K
Sale	Common Stock ^{F1, F4}	1,891	$30.264	$57K

Holdings After Transaction: Common Stock — 78,995 shares (Direct)

Footnotes (5)

F1. This transaction was made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on December 10, 2025.
F2. This transaction was executed in multiple trades at prices ranging from $28.150 to $29.140, 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.
F3. This transaction was executed in multiple trades at prices ranging from $29.150 to $30.130, 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.
F4. This transaction was executed in multiple trades at prices ranging from $30.150 to $30.645, 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.
F5. This transaction was executed in multiple trades at prices ranging from $28.030 to $28.630, 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

Total shares sold: 19,040 shares Sale on 2026-07-31 (tranche 1): 8,149 shares at $28.8420 per share Sale on 2026-07-31 (tranche 2): 7,270 shares at $29.5790 per share +3 more

6 metrics

Total shares sold 19,040 shares Aggregate common shares sold by Juvenal Tobin across all reported transactions

Sale on 2026-07-31 (tranche 1) 8,149 shares at $28.8420 per share Common stock sale coded S, weighted-average price on July 31, 2026

Sale on 2026-07-31 (tranche 2) 7,270 shares at $29.5790 per share Common stock sale coded S, weighted-average price on July 31, 2026

Sale on 2026-07-31 (tranche 3) 1,891 shares at $30.2640 per share Common stock sale coded S, weighted-average price on July 31, 2026

Sale on 2026-08-03 1,730 shares at $28.2500 per share Common stock sale coded S, weighted-average price on August 3, 2026

Rule 10b5-1 plan adoption date December 10, 2025 Date Juvenal Tobin adopted the Rule 10b5-1 trading plan governing these sales

Key Terms

Rule 10b5-1 plan, weighted-average sale price, Sale in open market or private transaction

3 terms

Rule 10b5-1 plan regulatory

"This transaction was 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

"The price reported above reflects the weighted-average sale price."

Sale in open market or private transaction financial

"transaction code description: Sale in open market or private transaction"

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/04/2026 - 04:36 PM Accepted by SEC EDGAR 08/04/2026 - 04:36 PM

FAQ

What insider activity did Castle Biosciences (CSTL) report for Juvenal Tobin?

Castle Biosciences reported that Chief Commercial Officer Juvenal Tobin sold 19,040 shares of CSTL common stock in four open‑market or private transactions on July 31 and August 3, 2026, as disclosed in a Form 4 insider trading report.

How many CSTL shares did Juvenal Tobin sell and on which dates?

Juvenal Tobin sold a total of 19,040 CSTL shares. He sold 17,310 shares on July 31, 2026 in three tranches and an additional 1,730 shares on August 3, 2026, according to the reported transactions.

At what prices were Juvenal Tobin’s CSTL stock sales executed?

The reported weighted‑average sale prices were $28.8420, $29.5790, and $30.2640 per share on July 31, 2026, and $28.2500 per share on August 3, 2026. Each reflects multiple trades aggregated into a single weighted‑average sale price.

Were Juvenal Tobin’s Castle Biosciences (CSTL) sales under a Rule 10b5-1 plan?

Yes. The transactions were made pursuant to a Rule 10b5‑1 trading plan that Juvenal Tobin adopted on December 10, 2025, and the filing’s Rule 10b5‑1 checkbox is marked as affirming plan‑based trades.

What is Juvenal Tobin’s role at Castle Biosciences (CSTL)?

Juvenal Tobin is the company’s Chief Commercial Officer. The reported Form 4 transactions involve his direct ownership of Castle Biosciences common stock, with sales coded as open‑market or private transactions.

How many separate transactions did the CSTL Form 4 report for Juvenal Tobin?

The Form 4 reports four non‑derivative transactions in Castle Biosciences common stock for Juvenal Tobin, all coded as “S” for sale and classified as sales in open‑market or private transactions.

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).

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)
07/31/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	07/31/2026		S⁽¹⁾		8,149	D	$28.842⁽²⁾	89,886	D
Common Stock	07/31/2026		S⁽¹⁾		7,270	D	$29.579⁽³⁾	82,616	D
Common Stock	07/31/2026		S⁽¹⁾		1,891	D	$30.264⁽⁴⁾	80,725	D
Common Stock	08/03/2026		S⁽¹⁾		1,730	D	$28.25⁽⁵⁾	78,995	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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 $28.150 to $29.140, 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 $29.150 to $30.130, 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.

4. This transaction was executed in multiple trades at prices ranging from $30.150 to $30.645, 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.

5. This transaction was executed in multiple trades at prices ranging from $28.030 to $28.630, 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	08/04/2026
	** 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)

Source: View Original Filing on SEC EDGAR