Castle Biosciences CCO plans $441K stock sale

A Castle Biosciences executive filed a Rule 144 notice to sell 13,177 shares under a Rule 10b5-1 trading plan.

Rhea-AI Filing Summary

CASTLE BIOSCIENCES INC (CSTL) received a notice that Tobin Juvenal, Chief Commercial Officer, has filed to sell 13,177 shares of common stock under Rule 144 through Goldman Sachs & Co. LLC. The planned sales have an aggregate market value of $440,638.88 based on recent prices.

The shares were acquired as equity compensation through restricted stock units and awards granted between December 2022 and March 2025. The filing states that these sales are made in connection with a Rule 10b5-1(c) selling plan dated May 28, 2026.

Key Figures

Shares to be sold under Rule 144: 13,177 shares Aggregate market value of planned sale: $440,638.88 Shares outstanding: 30,549,507 shares +4 more

7 metrics

Shares to be sold under Rule 144 13,177 shares Planned sale of Castle Biosciences common stock by Tobin Juvenal

Aggregate market value of planned sale $440,638.88 Value of 13,177 shares covered by the Rule 144 notice

Shares outstanding 30,549,507 shares Castle Biosciences common stock outstanding as referenced in the notice

Recent sale on July 31, 2026 17,310 shares Common stock sold by Tobin Juvenal on July 31, 2026

Proceeds from July 31, 2026 sale $507,303.86 Value of 17,310 shares of common stock sold on July 31, 2026

Sale on August 25, 2026 9,050 shares Common stock sold by Tobin Juvenal on August 25, 2026

Proceeds from August 25, 2026 sale $317,112.09 Value of 9,050 shares of common stock sold on August 25, 2026

Key Terms

Rule 144, Rule 10b5-1(c), Restricted Stock Units, Restricted Stock Awards

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Rule 10b5-1(c) regulatory

"selling plan dated 5/28/2026 that is intended to comply with Rule 10b5-1(c)."

Rule 10b5-1(c) is an SEC guideline that lets company insiders set up a written, pre-planned schedule to buy or sell their company stock when they are not in possession of material, nonpublic information. For investors, it matters because such plans can reduce the appearance of insider trading by separating decisions from inside knowledge—like putting your trades on autopilot—while also requiring scrutiny since pre-planned trades can still affect market confidence and share value.

Restricted Stock Units financial

"Acquired as compensation -- Restricted Stock Units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Restricted Stock Awards financial

"Acquired as compensation -- Restricted Stock Awards"

Restricted stock awards are company shares given to employees or executives that cannot be sold or transferred until certain conditions — like staying with the company for a set time or meeting performance targets — are met, like a gift that is locked in a safe until rules are satisfied. Investors care because these awards tie management’s pay to company performance, can increase the number of shares outstanding when they become tradable (dilution), and may signal expected future selling pressure or commitment to long-term growth.

FAQ

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

How many CSTL shares are planned for sale in this Form 144 filing?

The notice covers the planned sale of 13,177 shares of Castle Biosciences common stock through Goldman Sachs & Co. LLC under Rule 144.

Who is selling CSTL shares in this Form 144 and in what capacity?

The filing is for the account of Tobin Juvenal, who is identified as Chief Commercial Officer of Castle Biosciences, Inc.

What is the approximate market value of the CSTL shares to be sold?

The filing lists an aggregate market value of $440,638.88 for the 13,177 shares of Castle Biosciences common stock to be sold.

Were the CSTL shares being sold acquired as compensation?

Yes. The shares were acquired as compensation through restricted stock units on December 10, 2022 and March 4, 2025, and restricted stock awards on February 28, 2023.

Is the CSTL Form 144 sale under a Rule 10b5-1 trading plan?

Yes. The remarks state that the sales are made in connection with a selling plan dated May 28, 2026 that is intended to comply with Rule 10b5-1(c).

How many CSTL shares are outstanding according to this filing?

The Rule 144 notice reports that there are 30,549,507 shares of Castle Biosciences common stock outstanding.

What CSTL share sales has Tobin Juvenal made in the past three months?

The filing lists sales of 17,310 shares on July 31, 2026, and additional sales including 9,050 shares on August 25, 2026, along with several smaller transactions earlier in August 2026.

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

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Available on EDGAR 09/14/2026 - 06:00 PM Accepted by SEC EDGAR 09/14/2026 - 06:00 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001856542
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Castle Biosciences, Inc.
SEC File Number	001-38984
Address of Issuer	1500 W. Parkwood Ave Suite 400 Friendswood TEXAS 77546
Phone	1-866-788-9007
Name of Person for Whose Account the Securities are To Be Sold	Tobin Juvenal
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Chief Commercial Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Goldman Sachs & Co. LLC 200 West Street New York NY 10282	13177	440638.88	30549507	09/14/2026	NASD

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	12/10/2022	Acquired as compensation -- Restricted Stock Units	Issuer			4260	12/10/2022	Compensation
Common	03/04/2025	Acquired as compensation -- Restricted Stock Units	Issuer			8238	03/04/2025	Compensation
Common	02/28/2023	Acquired as compensation -- Restricted Stock Awards	Issuer			679	02/28/2023	Compensation

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Tobin Juvenal 1500 W. Parkwood Ave Suite 400 Friendswood TX 77546	Common	07/31/2026	17310	507303.86
Tobin Juvenal 1500 W. Parkwood Ave Suite 400 Friendswood TX 77546	Common	08/03/2026	1730	48873.34
Tobin Juvenal 1500 W. Parkwood Ave Suite 400 Friendswood TX 77546	Common	08/17/2026	1730	51191.84
Tobin Juvenal 1500 W. Parkwood Ave Suite 400 Friendswood TX 77546	Common	08/25/2026	9050	317112.09
Tobin Juvenal 1500 W. Parkwood Ave Suite 400 Friendswood TX 77546	Common	08/31/2026	1730	56760.97

144: Remarks and Signature

Remarks	The sales of shares set forth herein are made in connection with a selling plan dated 5/28/2026 that is intended to comply with Rule 10b5-1(c).
Date of Notice	09/14/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	05/28/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	Goldman Sachs & Co. LLC on behalf of Tobin Juvenal
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)