According to a recent Form 4 filing submitted to the Securities and Exchange Commission, Derek Maetzold, serving as President and Chief Executive Officer of Castle Biosciences Inc. (NASDAQ: CSTL), engaged in several significant transactions involving the company's common stock on May 7, 2026. The activity included the sale of shares totaling $217,904 alongside the acquisition of shares valued at $14,851.
These financial moves were executed as part of a Rule 10b5-1 trading plan. This specific type of automated trading arrangement was originally adopted by Maetzold on December 3, 2025, to govern the timing and nature of his transactions with the company's equity.
Detailed Breakdown of Share Dispositions
The total volume of shares sold by Maetzold amounted to 9,036 shares of common stock, resulting in a combined value of $217,904. The pricing for these sales was not uniform; rather, the weighted average sale prices fluctuated between $22.08 and $22.585 per share. These disposals were split between shares held directly by Maetzold and various holdings managed indirectly through several trusts.
In terms of direct ownership, Maetzold sold 5,308 shares at a weighted average price of $22.08 per share. Additionally, he sold 906 shares at a weighted average price of $22.585 per share.
The indirect sales through trusts are categorized as follows:
- The Maetzold Descendants 2020 Trust: This entity sold 1,159 shares at a weighted average of $22.08 and another 198 shares at a weighted average price of $22.585. The beneficiaries of this trust include Maetzold's spouse and children, with his spouse acting as the trustee.
- The Derek Maetzold 2020 Irrevocable Trust: Maetzold serves as the trustee for this trust, which benefits his children. This trust sold 985 shares at a weighted average price of $22.08 and 168 shares at a weighted average of $22.585.
- Maetzold 2018 Remainder Trusts: Four separate trusts—FBO Emily Carol Kirk, Hannah Elizabeth Maetzold, John Derek Maetzold, and Peter Douglas Maetzold—each participated in the sales. For each of these four trusts, Maetzold acted as trustee for his children (the beneficiaries). Each trust sold 237 shares at a weighted average price of $22.08 and 41 shares at an average price of $22.585.
Acquisitions and Current Holding Positions
While liquidating common stock, Maetzold also increased his share count through the exercise of fully vested stock options. He acquired 6,214 shares of common stock at a price of $2.39 per share, representing a total acquisition value of $14,851.
Following these May 7 transactions, Maetzold's direct holdings in Castle Biosciences common stock stand at 21,479 shares. His indirect holdings remain substantial across several vehicles:
- The Maetzold Descendants 2020 Trust holds 46,138 shares.
- The Derek Maetzold 2020 Irrevocable Trust holds 39,214 shares.
- Each of the four Maetzold 2018 Remainder Trusts holds 2,224 shares.
- DJM Grantor Retained Annuity Trust No. 5 holds 85,959 shares.
- DJM Grantor Retained Annuity Trust No. 6 holds 18,718 shares.
- DJM Grantor Retained Annuity Trust No. 7 holds 44,323 shares.
Furthermore, Maetzold's derivative holdings in the form of stock options have decreased to a total of 754 shares.
Financial Context and Market Performance
These insider activities occur against a backdrop of recent financial reporting from Castle Biosciences. The company recently released its first-quarter 2026 earnings, which demonstrated notable revenue growth. Reported revenue reached $83.7 million, outperforming the initial projections of $77.46 million. While the company reported an earnings per share (EPS) loss of $0.49, this figure was in line with expectations from analysts. These results contributed to a modest increase in after-hours trading activity.
From a valuation perspective, some analysis suggests that Castle Biosciences may be currently undervalued. The stock is trading at levels below its estimated Fair Value. Additionally, the company's balance sheet shows healthy financial standing, characterized by a "GOOD" financial health score and holding more cash than debt. Market analysts have provided price targets for CSTL ranging from $40 to $52, implying potential upside relative to current market pricing.