X0306 4 2021-02-01 0 0001527753 Personalis, Inc. PSNL 0001779787 Chen Richard C/O PERSONALIS, INC. 1330 O'BRIEN DRIVE MENLO PARK CA 94025 0 1 0 0 Chief Scientific Officer Common Stock 2021-02-01 4 S 0 6519 38.19 D 104851 D Common Stock 2021-02-01 4 S 0 20059 38.83 D 84792 D Common Stock 2021-02-01 4 M 0 13422 0.44 A 98214 D Common Stock 2021-02-01 4 S 0 2400 38.12 D 95814 D Common Stock 2021-02-01 4 S 0 11022 38.80 D 84792 D Stock Option (Right to Buy) 0.44 2021-02-01 4 M 0 13422 0.00 D 2022-03-07 Common Stock 13422 18462 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan by the reporting person. The weighted average sale price for the transaction reported was $38.19, and the range of prices were between 37.56 and 38.54. Upon request from the SEC staff, the issuer, or any security holder of the issuer, full information regarding the number of shares sold at each separate price will be provided. The weighted average sale price for the transaction reported was $38.83, and the range of prices were between 38.57 and 39.28. Upon request from the SEC staff, the issuer, or any security holder of the issuer, full information regarding the number of shares sold at each separate price will be provided. The weighted average sale price for the transaction reported was $38.12, and the range of prices were between 37.56 and 38.54. Upon request from the SEC staff, the issuer, or any security holder of the issuer, full information regarding the number of shares sold at each separate price will be provided. The weighted average sale price for the transaction reported was $38.80, and the range of prices were between 38.58 and 39.28. Upon request from the SEC staff, the issuer, or any security holder of the issuer, full information regarding the number of shares sold at each separate price will be provided. The Shares subject to the option are fully vested and exercisable. /s/ Aaron Tachibana, Attorney-in-Fact 2021-02-03