Julie Rubinstein, President and COO of Adaptive Biotechnologies (ADPT), has filed 137 Form 4 transactions, all in that single company. The pattern is entirely one-sided: she has reported zero open-market purchases and zero acquisitions, while her total open-market sales reach $18,029,977.51. The recent activity, spanning October 8 through October 21, 2026, consists of 15 sales and 10 option exercises, with no buys in that window.
The daily rhythm is mechanical. On each trading day from October 8 to October 21, Rubinstein exercised options valued at $144,235.34 and then sold shares in the same session. For example, on October 21 she sold $150,402.74 and $151,474.75 worth of stock, paired with the option exercise. The sale sizes vary, from small amounts like $2,485 on October 20 to larger blocks such as $313,777.21 on October 9. The option exercises are coded "M," which is a mechanical conversion of existing awards, not a fresh purchase. The sales are coded "S," open-market dispositions.
The data shows a consistent sell bias. Rubinstein has not used a "P" code, the only transaction type that signals a voluntary open-market purchase, at any point in the filing history. The recent cluster of sales, each paired with an exercise, suggests she is converting vested options into cash rather than building a larger position. The total dollar value of sales, roughly $18.03 million, dwarfs any acquisition activity, which sits at zero. The transactions are concentrated in ADPT, and the direction over the past two weeks has been uniformly toward reducing her holdings.
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