Overview
Derek J. Maetzold, President and Chief Executive Officer of Castle Biosciences Inc (NASDAQ:CSTL), disposed of 19,300 shares of the company’s common stock across two days in mid-March 2026, according to a Form 4 filing. The combined proceeds from the sales amounted to $500,098.
Transaction details
On March 17, Maetzold sold 18,650 shares at an average reported price of $25.93 per share, producing $483,694.50 in proceeds. The Form 4 entry indicates those shares were sold in multiple trades at prices ranging from $25.66 to $26.27. After completing the March 17 transactions, Maetzold is reported to directly own 22,129 shares.
On March 18, he sold an additional 650 shares at $25.39 per share, for a total of $16,503.50. The March 18 sales were executed at prices between $25.26 and $25.48. Following that sale, his direct holdings stood at 21,479 shares.
Ownership structure noted in filing
The filing also lists indirect holdings attributable to Maetzold through several trust vehicles. These include The Maetzold Descendants 2020 Trust, the Derek Maetzold 2020 Irrevocable Trust, various Maetzold 2018 Remainder Trusts, and DJM Grantor Retained Annuity Trusts.
Planned trading arrangement
The reported sales were carried out pursuant to a Rule 10b5-1 trading plan that Maetzold adopted on December 3, 2025. The Form 4 reflects the mechanics and dates of the executed trades but does not provide additional commentary on motivations beyond the 10b5-1 plan framework.
Market context and analyst view
At the time of the filing, Castle Biosciences shares were trading near $25.70. The stock has declined about 34% year-to-date but has rebounded roughly 76% from its 52-week low of $14.59. The article notes that InvestingPro analysis considers the shares undervalued at current levels, with analysts maintaining price targets in the $44 to $52 range.
Recent financial results
Castle Biosciences reported fourth-quarter 2025 results that exceeded expectations on both the earnings and revenue lines. The company posted a diluted loss per share of $0.08, compared with a consensus forecast loss of $0.32, which the filing characterizes as a 75% positive surprise. Revenue for the quarter was $87.0 million, ahead of the anticipated $77.09 million by 12.86%.
The revenue improvement was attributed in the report to higher year-over-year volumes for most of the company’s tests, consistent with the company’s prior preannouncement. Following the results, Canaccord Genuity reiterated a Buy rating on Castle Biosciences and set a $50 price target.
Note: The Form 4 filing provides the transaction specifics and the filing lists Maetzold’s direct and indirect holdings. The submission also states that the trades were conducted under the previously adopted Rule 10b5-1 trading plan.