X0306 4 2021-09-08 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001780649 ROBINS CHAD M C/O ADAPTIVE BIOTECHNOLOGIES CORPORATION 1551 EASTLAKE AVE E STE 200 SEATTLE WA 98102 1 1 0 0 CEO and Chairman Common Stock 2021-09-08 4 S 0 11742 38.34 D 1705218 D Common Stock 2021-09-08 4 S 0 2004 39.11 D 1703214 D Common Stock 2021-09-09 4 S 0 24753 38.42 D 1678461 D Common Stock 2021-09-10 4 S 0 4902 38.37 D 1673559 D Common Stock 2021-09-10 4 S 0 98 39.09 D 1673461 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 22, 2020. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $38.00 to 38.98, 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 $39.01 to 39.37, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $38.15 to 38.73, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $38.02 to 38.99, inclusive. /s/ Chad Robins by Eric Billings, Attorney-in-Fact 2021-09-10