Derek J. Maetzold, president and chief executive officer of Castle Biosciences (CSTL), has filed 159 Form 4 transactions, all in that single company. The pattern is one-sided. His total sell value is $11,779,084.09, and his total buy value is zero. He has not made an open-market purchase in the recent period, and his recent activity consists of 21 sales.
The recent trades cluster on four dates: August 14, August 28, September 11, and September 21, 2026. Each date shows a mix of open-market sales (code S) and option exercises (code M). The option exercises are small, ranging from $2,629 to $29,702.92, and are mechanical in nature. The sales are the substantive transactions. On September 21 alone, he sold $512,201.66 worth of CSTL shares across three separate trades, the largest being $303,165.72. The August 28 sales totaled $588,448.26, including one block of $380,182.08. The September 11 sales came to $464,870.06, and the August 14 sales to $192,067.96.
The dollar values vary widely, from a $711.48 sale on August 28 to the $380,182.08 block on the same day. This suggests routine portfolio management rather than a single large disposition. The absence of any purchases, combined with the steady stream of sales across four weeks, shows a consistent selling bias. The option exercises that accompany each sale date are standard compensation mechanics, not discretionary buys. The data offers no evidence of accumulation. Maetzold's Form 4 history is a record of regular, repeated sales of CSTL stock, with no offsetting open-market buying.
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