X0306 4 2021-01-25 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001524314 Cohen Chad M C/O ADAPTIVE BIOTECHNOLOGIES CORP. SUITE 200 SEATTLE WA 98102 0 1 0 0 Chief Financial Officer Common Stock 2021-01-25 4 M 0 50000 6.32 A 51000 D Common Stock 2021-01-25 4 S 0 10611 65.08 D 40389 D Common Stock 2021-01-25 4 S 0 20953 65.69 D 19436 D Common Stock 2021-01-25 4 S 0 17436 67.03 D 2000 D Common Stock 2021-01-25 4 S 0 1000 67.68 D 1000 D Common Stock 2021-01-26 4 M 0 50000 6.32 A 51000 D Common Stock 2021-01-26 4 S 0 10318 62.71 D 40682 D Common Stock 2021-01-26 4 S 0 12977 63.65 D 27705 D Common Stock 2021-01-26 4 S 0 20785 64.54 D 6920 D Common Stock 2021-01-26 4 S 0 5920 65.47 D 1000 D Stock Option (Right to Buy) 6.32 2021-01-25 4 M 0 50000 0.00 D 2025-08-25 Common Stock 50000 215000 D Stock Option (Right to Buy) 6.32 2021-01-26 4 M 0 50000 0.00 D 2025-08-25 Common Stock 50000 165000 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 $64.35 to 65.345, 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 $65.35 to 66.32, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $66.55 to $67.53, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $67.56 to 67.79, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $62.14 to 63.12, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $63.14 to 64.04, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $64.285 to 65.255, inclusive. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $65.31 to 66.01, inclusive. The option is fully vested and exercisable. /s/ Chad Cohen by Eric Billings, Attorney-in-Fact 2021-01-27