X0306 4 2022-03-08 0 0001478320 Adaptive Biotechnologies Corp ADPT 0001780773 BALDO LANCE 1165 EASTLAKE AVENUE E SEATTLE WA 98109 0 1 0 0 Chief Medical Officer Common Stock 2022-03-08 4 S 0 3350 11.43 D 17171 D The transaction reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 12, 2021. The price reported for this transaction is a weighted-average price. The shares were sold in multiple transactions ranging from $11.28 to 11.65, 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. /s/ Lance Baldo by Eric Billings, attorney-in-fact 2022-03-10