CSTL Form 144: Proposed sale of 20,863 shares

CSTL filed a Form 144 reporting proposed sales of Common Stock.

Rhea-AI Filing Summary

CSTL filed a Form 144 reporting proposed sales of Common Stock. The notice lists 20,863 shares with an aggregate market value of $528,251.16 and records a prior sale of 13,200 shares on 12/11/2025 by Tobin Juvenal. The filing identifies recent grants of restricted and performance stock units dated 03/03/2026 and 03/04/2026.

Insights

Securities Attorney

Routine resale notice under Rule 144; regulatory mechanics matter.

The filing is a regulatory notice of proposed resale of restricted/performance-derived shares and prior disposition by a named seller. It lists $528,251.16 as an aggregate market value and a quantity of 20,863 shares.

Whether sales occur depends on Rule 144 conditions and broker handling; subsequent filings will show actual transactions and settlement details.

Equity Markets Analyst

Administrative Form 144 with limited market impact in isolation.

The notice catalogs proposed resale quantities and recent grant dates (03/03/2026 and 03/04/2026) including restricted and performance stock units. It also records a prior disposition of 13,200 shares on 12/11/2025.

Actual market impact will depend on if and when those shares are sold and trade execution; subsequent transaction filings would clarify timing and scale.

FAQ

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

What does the CSTL Form 144 report?

The filing reports a proposed resale of Common Stock, listing 20,863 shares and an aggregate market value of $528,251.16. It also notes a prior sale of 13,200 shares on 12/11/2025 by Tobin Juvenal.

Who is the seller named in the CSTL Form 144?

The filing names Tobin Juvenal as a prior seller, reporting a sale of 13,200 shares on 12/11/2025. Other rows list shares acquired as restricted or performance stock units on 03/03/2026 and 03/04/2026.

Does the Form 144 mean CSTL shares have already been sold?

No; the Form 144 is a notice of proposed resale and records a prior sale separately. The listing of 20,863 shares and market value signals intent, not completed market transactions; subsequent filings would show completed sales.

What types of securities are listed in the CSTL Form 144?

The notice lists Common Stock acquired as Restricted Stock Units and Performance Stock Units, with grant dates of 03/03/2026 and 03/04/2026. It also documents prior dispositions in the past three months.

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

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Accepted by SEC EDGAR 03/12/2026 - 04:38 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	20863	528251.16	29731198	03/12/2026	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	03/04/2026	Acquired as compensation -- Restricted Stock Units	Issuer			8238	03/04/2026	Compensation
Common	03/04/2026	Acquired as compensation -- Restricted Stock Units	Issuer			7134	03/04/2026	Compensation
Common	03/03/2026	Acquired as compensation- Performance Stock Units	Issuer			5491	03/03/2026	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	12/11/2025	13200	494736

144: Remarks and Signature

Remarks	The sales of shares set forth herein are made in connection with a selling plan dated 12/10/2025 that is intended to comply with Rule 10b5-1(c).
Date of Notice	03/12/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	12/10/2025
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)