X0306 4 2021-03-15 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001780854 BENZENO SHARON C/O ADAPTIVE BIOTECHNOLOGIES CORP. SUITE 200 SEATTLE WA 98102 0 1 0 0 Chief Business Development Off Common Stock 2021-03-15 4 M 0 1354 31.71 A 24248 D Common Stock 2021-03-15 4 S 0 340 41.22 D 23908 D Common Stock 2021-03-15 4 S 0 1014 41.85 D 22894 D Stock Option (Right to Buy) 31.71 2021-03-15 4 M 0 1354 0.00 D 2030-02-13 Common Stock 1354 47396 D The transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 16, 2020. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $40.51 to 41.50, 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 price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $41.51 to 42.31, inclusive. The options vested with respect to 1/4 of such shares on February 13, 2021, with 1/48 of such shares vesting thereafter at the end of each full month of continuous service until fully vested. /s/ Sharon Benzeno by Eric Billings as attorney-in-fact 2021-03-17