Form 144: Proposed Sale of 4,748 Common Shares

CSTL submitted a Form 144 notice reporting a proposed sale of 4,748 common shares via a stock option exercise dated 03/05/2026.

Rhea-AI Filing Summary

CSTL submitted a Form 144 notice reporting a proposed sale of 4,748 common shares via a stock option exercise dated 03/05/2026.

Broker/dealer listed is Morgan Stanley Smith Barney LLC. The filing also lists previously issued restricted stock quantities of 830 (06/10/2022) and 1,825 (06/02/2023).

FAQ

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What does the CSTL Form 144 disclose about the securities to be sold?

It reports a proposed sale of 4,748 common shares via stock option exercise on 03/05/2026. The item is filed under a Form 144 notice and identifies the sale method as a stock option exercise and the sale date as 03/05/2026.

Which broker/dealer is named on the CSTL Form 144 filing?

Morgan Stanley Smith Barney LLC is listed as the broker/dealer in the filing. The document includes the broker's address line showing "Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004" alongside the broker name.

Does the filing show any restricted stock information for CSTL?

Yes. The filing lists restricted stock entries of 830 shares with grant date 06/10/2022 and 1,825 shares with grant date 06/02/2023, each identified as restricted stock issued by the issuer.

What transaction method and date are specified for the CSTL sale?

Transaction method: Stock option exercise. Date: 03/05/2026. The filing explicitly pairs the sale method "Stock Option Exercise" with the date 03/05/2026 and the quantity 4,748 common shares.

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

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Accepted by SEC EDGAR 03/05/2026 - 04:04 PM EST 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	0001337798
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	866-788-9007
Name of Person for Whose Account the Securities are To Be Sold	GORDON B. COLE
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	Director

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	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	7403	210742.54	29731198	03/05/2026	NASDAQ

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	03/05/2026	Stock Option Exercise	Issuer			4748	03/05/2026	Cash
Common	06/10/2022	Restricted Stock	Issuer			830	06/10/2022	Not Applicable
Common	06/02/2023	Restricted Stock	Issuer			1825	06/02/2023	Not Applicable

* 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

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	03/05/2026
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	/s/ Gordon Bradley Cole
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)