[144] Castle Biosciences, Inc. SEC Filing

Rhea-AI Filing Summary

Form 144 filing for Castle Biosciences, Inc. (CSTL) shows a proposed Rule 144 sale of 18,007 shares of common stock through J.P. Morgan Securities LLC on 08/27/2025 on NASDAQ with an aggregate market value of $384,449.45. The shares stem from restricted stock units granted by the issuer: 10,171 RSUs acquired 03/04/2025 and 7,836 RSUs acquired 08/08/2025, with payment characterized as compensation. No sales by the reporting person in the past three months are reported. The filer attests there is no undisclosed material adverse information.

Positive

• Transparent disclosure of the number of shares, aggregate market value, acquisition dates, and broker details under Rule 144
• Securities derive from RSUs granted by the issuer and are characterized as compensation, indicating standard vesting-related liquidity

Negative

• Insider sale of 18,007 shares could modestly increase supply of shares available for trading
• Short interval between acquisition and proposed sale for the 08/08/2025 RSUs (sale same month) which may attract attention despite being compliant

Insights

Securities Analyst

TL;DR: Routine insider sale of recently vested RSUs totaling 18,007 shares worth ~$384k; likely limited market impact.

The filing documents a straightforward Rule 144 notice for holdings derived from restricted stock units that were acquired as compensation in 2025. The transaction is brokered through a major dealer and the sale size represents a small fraction of the 29,008,281 outstanding shares reported in the form. From a market perspective this is a typical liquidity event for an insider and does not indicate unusual trading patterns based on the information provided.

Corporate Governance Expert

TL;DR: Compliance-focused disclosure showing adherence to Rule 144 requirements; no governance red flags stated.

The filer discloses acquisition dates and nature of acquisition (RSUs) and confirms the statutory representation about lack of undisclosed material information. The use of an institutional broker and explicit compensation payment characterization are consistent with standard executive equity vesting and monetization. There is no evidence in this filing of accelerated insider disposals or exceptions to normal disclosure practices.

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	18007	384449.45	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	03/04/2025	Restricted Stock Unit	Issuer			10171	03/04/2025	Compensation
Common Stock	08/08/2025	Restricted Stock Unit	Issuer			7836	08/08/2025	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

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

How many Castle Biosciences (CSTL) shares are proposed for sale?

The filing proposes sale of 18,007 shares of Castle Biosciences common stock.

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

The aggregate market value is reported as $384,449.45.

When and where is the CSTL sale expected to occur?

The sale is approximately dated for 08/27/2025 on NASDAQ via J.P. Morgan Securities LLC.

What is the origin of the securities being sold?

The securities were acquired as Restricted Stock Units (RSUs) from the issuer on 03/04/2025 (10,171 shares) and 08/08/2025 (7,836 shares).

Are there any reported sales by the filer in the past three months?

The filing states Nothing to Report for securities sold during the past three months.