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  4. [144] CASTLE BIOSCIENCES INC SEC Filing

Castle Biosciences officer proposes $749K share sale

The planned sales are linked to a June 2, 2026 selling plan intended to comply with Rule 10b5-1(c).

Available on EDGAR Accepted by SEC EDGAR
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Form Type
144

Rhea-AI Filing Summary

Castle Biosciences, Inc. (CSTL) officer Derek Maetzold reported a proposed sale of 21,438 common shares, with an approximate sale date of November 2, 2026, through Goldman Sachs & Co. LLC. The stated aggregate market value is $749,043.72. The total comprises 12,484 shares by Derek Maetzold, 4,114 by Derek Maetzold 2020 Irrevocable Trust, and 4,840 by The Maetzold Descendants 2020 Trust. The planned sales are in connection with a selling plan dated June 2, 2026, intended to comply with Rule 10b5-1(c).

Proposed sale 21,438 common shares Approximate sale date November 2, 2026
Aggregate market value $749,043.72 Proposed sale
Shares outstanding 30,549,507 shares Issuer shares outstanding listed in the notice
Shares attributed to Derek Maetzold 12,484 shares Component of proposed sale
Shares attributed to Derek Maetzold 2020 Irrevocable Trust 4,114 shares Component of proposed sale
Shares attributed to The Maetzold Descendants 2020 Trust 4,840 shares Component of proposed sale
Rule 10b5-1(c) regulatory
"intended to comply with Rule 10b5-1(c)"
Rule 10b5-1(c) is an SEC guideline that lets company insiders set up a written, pre-planned schedule to buy or sell their company stock when they are not in possession of material, nonpublic information. For investors, it matters because such plans can reduce the appearance of insider trading by separating decisions from inside knowledge—like putting your trades on autopilot—while also requiring scrutiny since pre-planned trades can still affect market confidence and share value.
Rule 144 regulatory
"sales required by paragraph (e) of Rule 144"
Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

FAQ

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

How many CSTL shares does Derek Maetzold plan to sell?
The proposed sale covers 21,438 common shares: 12,484 by Derek Maetzold, 4,114 by Derek Maetzold 2020 Irrevocable Trust, and 4,840 by The Maetzold Descendants 2020 Trust. The planned sales are in connection with a selling plan dated June 2, 2026, intended to comply with Rule 10b5-1(c).

What is the listed value of Derek Maetzold's proposed CSTL share sale?
The proposed sale has a stated aggregate market value of $749,043.72.

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

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144: Filer Information

144: Issuer Information

144: Securities Information



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


* 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

144: Remarks and Signature

Source: View Original Filing on SEC EDGAR

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