X0508 4 2025-11-28 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001780662 PISKEL KYLE C/O ADAPTIVE BIOTECHNOLOGIES CORPORATION 1165 EASTLAKE AVE E SEATTLE WA 98109 0 1 0 0 Chief Financial Officer 1 Common Stock 2025-11-28 4 M 0 11980 6.55 A 281323 D Common Stock 2025-11-28 4 M 0 3750 7.8 A 285073 D Common Stock 2025-11-28 4 M 0 94384 12.14 A 379457 D Common Stock 2025-11-28 4 S 0 162820 19.5 D 216637 D Stock Option (right to buy) 6.55 2025-11-28 4 M 0 11980 0 D 2028-10-01 Common Stock 11980 0 D Stock Option (right to buy) 7.8 2025-11-28 4 M 0 3750 0 D 2029-04-23 Common Stock 3750 0 D Stock Option (right to buy) 12.14 2025-11-28 4 M 0 94384 0 D 2032-03-04 Common Stock 94384 8581 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 28, 2025. The price reported for this transaction is a weighted -average price. The shares were sold in multiple transactions ranging from $19.28 to $19.72, inclusive. The reporting person undertakes to provide to Adaptive Biotechnologies Corporation, any security holder of Adaptive Biotechnologies Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in any footnotes to this Form 4. The option is fully vested and exercisable. The options vested with respect to 1/4 of such shares on March 4, 2023, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Kyle Piskel 2025-12-02