CSTL Form 144: 43,019 Performance Award Shares Routed to Goldman Sachs

Rhea-AI Filing Summary

Castle Biosciences (CSTL) disclosed a proposed sale of 43,019 common shares through Goldman Sachs & Co. LLC with an aggregate market value of $834,998.79. The form lists the approximate date of sale as 08/13/2025 and identifies the securities exchange as NASD. The shares were recorded as acquired on 08/08/2025 from the issuer as performance award compensation, with payment dated 08/08/2025. The filing also reports multiple related-party sales on 06/27/2025 by The Maetzold trusts and Derek Maetzold totaling specific share amounts and gross proceeds. The filer certifies compliance with Rule 144 and affirms no undisclosed material adverse information.

Positive

• Transaction is disclosed via Form 144, indicating compliance with Rule 144 and use of a major broker (Goldman Sachs & Co. LLC)
• Shares to be sold were acquired as performance awards, showing alignment of compensation with equity-based incentives

Negative

• Planned sale of 43,019 common shares (aggregate value $834,998.79) could be perceived negatively by some investors monitoring insider selling
• Multiple related-party sales on 06/27/2025 by The Maetzold trusts and Derek Maetzold are disclosed, showing prior liquidation activity by insiders/related parties

Insights

Securities Analyst

TL;DR: Insiders intend to sell 43,019 performance-award shares via Goldman Sachs; transaction size appears routine versus total outstanding shares.

The planned disposition is of shares recently acquired as performance compensation, routed through a major broker under Rule 144. The filing shows an aggregate market value of $834,998.79 against a reported 29,008,281 shares outstanding, indicating the sale is not a large block relative to total capitalization. Multiple related-party disposals on 06/27/2025 are disclosed, showing prior liquidity events by trusts and an individual. From a market-impact perspective this appears informational and compliant rather than materially dilutive.

Corporate Governance Expert

TL;DR: The disclosure documents conversion of compensation awards to marketable shares and routine sales by related parties; governance disclosure appears complete.

The form documents that the shares were acquired as performance awards from the issuer and are being offered for sale through an institutional broker, with the filer providing the standard Rule 144 representation about material information. The presence of several trust and individual sales in late June suggests prior planned liquidity by related parties. The filing itself raises no governance red flags but is relevant for stakeholders monitoring insider liquidity and executive compensation monetization.

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	Goldman Sachs & Co. LLC 200 West Street New York NY 10282	43019	834998.79	29008281	08/13/2025	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	08/08/2025	Acquired as compensation -- Performance Awards	Issuer			43019	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

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	8068	163804.6
The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	660	13399.98
The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	660	13399.98
Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	4944	100378.03
Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	6924	140577.97
The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	660	13399.98
The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546	Common	06/27/2025	660	13399.98

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 the Castle Biosciences (CSTL) Form 144 disclose?

The form discloses a proposed sale of 43,019 common shares through Goldman Sachs & Co. LLC with aggregate market value $834,998.79 and an approximate sale date of 08/13/2025.

How were the shares acquired that are being sold under the Form 144?

The shares were recorded as acquired on 08/08/2025 as compensation — performance awards from the issuer, with payment dated 08/08/2025.

Were there related insider or trust sales recently reported for CSTL?

Yes. The filing lists multiple sales on 06/27/2025 by The Maetzold Descendants 2020 Trust, The Maetzold 2018 Remainder Trusts, Derek Maetzold, and others, with individual share amounts and gross proceeds shown in the filing.

How many shares outstanding does Castle Biosciences report in the filing?

The filing shows 29,008,281 shares outstanding for the issuer.

Which broker and exchange are involved in the planned sale?

The broker is Goldman Sachs & Co. LLC and the securities exchange listed is NASD.