[144] Castle Biosciences, Inc. SEC Filing

Rhea-AI Filing Summary

Castle Biosciences (CSTL) submitted a Form 144 disclosing a proposed sale of 25,355 shares of common stock through J.P. Morgan Securities LLC on or about 08/27/2025 on the NASDAQ. The filing reports an aggregate market value of $541,329 against 29,008,281 shares outstanding. The shares originated from two Restricted Stock Unit grants received as compensation: 7,837 units acquired on 08/09/2024 and 17,518 units acquired on 12/09/2024, with payment/vesting dates matching acquisition dates. The filer certifies no undisclosed material adverse information and indicates this is a LIVE filing.

Positive

• Planned sale disclosed via Form 144 with broker, date, and aggregate value, supporting regulatory transparency
• Origin of shares specified as Restricted Stock Units granted as compensation on 08/09/2024 and 12/09/2024

Negative

• None.

Insights

Securities Analyst

TL;DR: Routine insider sale notice disclosing compensation-derived RSUs to be sold, modest relative to outstanding shares.

The Form 144 reports a proposed sale of 25,355 common shares valued at $541,329 via J.P. Morgan on NASDAQ. The shares stem from RSU grants received in August and December 2024 and were identified as compensation. Relative to 29,008,281 shares outstanding, the block represents about 0.087% of outstanding shares, indicating the sale is small in absolute company capital terms and consistent with routine insider liquidity activity. The filing contains no information about other sales in the past three months and includes the required certification regarding material nonpublic information.

Compliance/Risk Analyst

TL;DR: Filing appears compliant and standard, with required disclosures about source and certification against undisclosed material information.

The notice identifies the broker, proposed sale date, aggregate market value, and the origin of the securities as RSUs granted as compensation on specified dates. The filer marked the submission as LIVE and included the representation that they are unaware of undisclosed material adverse information. No 10b5-1 plan date or prior three-month sales are reported. Based solely on the form content, there are no explicit compliance exceptions or red flags disclosed within this filing.

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

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

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

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 Stock	J.P. Morgan Securities LLC 390 Madison Avenue, 6th Floor New York NY 10017	25355	541329	29008281	08/27/2025	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 Stock	08/09/2024	Restricted Stock Unit	Issuer			7837	08/09/2024	Compensation
Common Stock	12/09/2024	Restricted Stock Unit	Issuer			17518	12/09/2024	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

Nothing to Report

144: Remarks and Signature

Remarks

Date of Notice

Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1

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

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does Castle Biosciences (CSTL) disclose in this Form 144?

The filing discloses a proposed sale of 25,355 common shares through J.P. Morgan Securities LLC on or about 08/27/2025 with an aggregate market value of $541,329.

How were the CSTL shares being sold acquired?

All shares were acquired as Restricted Stock Units (RSUs) granted as compensation: 7,837 on 08/09/2024 and 17,518 on 12/09/2024.

What percentage of Castle Biosciences' outstanding stock is represented by this sale?

The sale of 25,355 shares represents approximately 0.087% of the reported 29,008,281 shares outstanding.

Did the filer report any securities sold in the past three months?

The Form 144 indicates "Nothing to Report" for securities sold during the past three months.

Does the filing state whether the filer knows of any undisclosed material information?

Yes. By signing the notice the person represents they do not know any material adverse information about the issuer that has not been publicly disclosed.