X0508 4 2025-12-22 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001780660 LO FRANCIS C/O ADAPTIVE BIOTECHNOLOGIES CORPORATION 1165 EASTLAKE AVE E SEATTLE WA 98109 0 1 0 0 Chief People Officer 1 Common Stock 2025-12-22 4 M 0 1100 7.8 A 317078 D Common Stock 2025-12-22 4 M 0 2194 8.46 A 319272 D Common Stock 2025-12-22 4 M 0 1100 3.99 A 320372 D Common Stock 2025-12-22 4 S 0 4394 17.5 D 315978 D Common Stock 2500 I By You Jin Lee (spouse) Stock Option (right to buy) 7.8 2025-12-22 4 M 0 1100 0 D 2029-05-06 Common Stock 1100 112150 D Stock Option (right to buy) 8.46 2025-12-22 4 M 0 2194 0 D 2033-03-06 Common Stock 2194 106982 D Stock Option (right to buy) 3.99 2025-12-22 4 M 0 1100 0 D 2034-03-04 Common Stock 1100 109075 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 15, 2025. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $17.49 to $17.50, 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, 2024, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. The options vested with respect to 1/4 of such shares on March 4, 2025, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Francis Lo by Kyle Piskel, Attorney-in-Fact 2025-12-29