Castle Biosciences, Inc. officer Derek Maetzold filed a Form 144 notice of proposed sale of 21,438 shares of common stock, with an approximate sale date of November 2, 2026, through Goldman Sachs & Co. LLC.

Key Highlights

  • Proposed shares: Derek Maetzold, an officer of Castle Biosciences, Inc., filed notice to sell 21,438 shares of common stock.
  • Aggregate market value: The proposed sale carries an aggregate market value of $749,043.72, according to the filing.
  • Shares outstanding: The filing reports 30,549,507 shares of common stock outstanding at the time of filing.
  • Broker named: Goldman Sachs & Co. LLC, 200 West Street, New York, NY 10282, is listed as the broker for the proposed sale.
  • Securities acquired via gifts and option exercises: The shares to be sold were acquired through gifts dated October 29, 2007 (4,840 and 4,114 shares), an option exercise on May 12, 2020 (8,683 shares), and an option exercise on March 5, 2024 (3,801 shares).
  • Recent prior sales: Multiple sales by Maetzold and related trusts were reported during the prior three months, including sales on August 3, 4, 5, 14, and 28, 2026, across Maetzold personally and several associated trusts.

Derek Maetzold's Proposed Rule 144 Sale at Castle Biosciences

According to the filing, Derek Maetzold, identified as an officer of Castle Biosciences, Inc. (listed on NASD, SEC File Number 001-38984), submitted a Form 144 notice proposing the sale of 21,438 shares of Castle Biosciences common stock. The approximate date of sale is listed as November 2, 2026. The filing reports the aggregate market value of the proposed sale at $749,043.72, with 30,549,507 shares of common stock outstanding at the time of filing.

The filing discloses that the shares subject to the proposed sale were acquired through a combination of transactions: two gifts dated October 29, 2007, totaling 8,954 shares (4,840 and 4,114 shares, each acquired as a gift from Derek Maetzold); an option exercise on May 12, 2020 covering 8,683 shares; and an option exercise on March 5, 2024 covering 3,801 shares. No cash consideration is indicated for the gifted shares; option exercise is listed as the nature of payment for the remaining shares.

The filing also discloses sales during the prior three months by Maetzold personally and by several related entities, including the Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020, The Maetzold Descendants 2020 Trust dtd 12/4/2020, and four Maetzold 2018 Remainder Trusts for the benefit of named individuals. These prior sales occurred on August 3, 4, 5, 14, and 28, 2026, and involved varying share amounts and gross proceeds across the listed sellers, as required to be aggregated under Rule 144.

What Was Disclosed

Castle Biosciences officer Derek Maetzold filed a Form 144 disclosing a proposed sale of 21,438 shares of common stock with an aggregate market value of $749,043.72, an approximate sale date of November 2, 2026, and prior three-month sales by Maetzold and associated trusts.