X0306 4 2021-09-07 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001524314 Cohen Chad M C/O ADAPTIVE BIOTECHNOLOGIES CORP. 1165 EASTLAKE AVENUE E SEATTLE WA 98102 0 1 0 0 Chief Financial Officer Common Stock 2021-09-07 4 M 0 9375 6.55 A 30979 D Common Stock 2021-09-07 4 S 0 9375 39.71 D 21604 D Common Stock 2021-09-08 4 M 0 5000 7.27 A 26604 D Common Stock 2021-09-08 4 S 0 5000 39.01 D 21604 D Stock Option (Right to Buy) 6.55 2021-09-07 4 M 0 9375 0.00 D 2028-02-07 Common Stock 9375 65625 D Stock Option (Right to Buy) 7.27 2021-09-08 4 M 0 5000 0.00 D 2029-02-07 Common Stock 5000 110000 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 16, 2020. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $39.25 to 39.97, 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 price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $38.765 to 39.50, inclusive. The options vested with respect to 1/4 of such shares on November 1, 2018, 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 January 1, 2020, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Chad Cohen by Eric Billings, Attorney-in-Fact 2021-09-09