X0306 4 2020-03-09 0 0001093557 DEXCOM INC DXCM 0001610762 ACE HEATHER S 6340 SEQUENCE DRIVE SAN DIEGO CA 92121 0 1 0 0 SVP Human Resources Common Stock 2020-03-09 4 S 0 227 261.5463 D 52449 D Common Stock 2020-03-09 4 S 0 300 262.0 D 52149 D Common Stock 2020-03-09 4 S 0 300 263.15 D 51849 D Common Stock 2020-03-09 4 S 0 100 264.93 D 51749 D Common Stock 2020-03-09 4 S 0 1500 267.1329 D 50249 D Common Stock 2020-03-09 4 S 0 1300 268.0696 D 48949 D Common Stock 2020-03-09 4 S 0 200 268.995 D 48749 D Common Stock 2020-03-09 4 S 0 200 270.505 D 48549 D Common Stock 2020-03-09 4 S 0 600 272.265 D 47949 D Common Stock 2020-03-09 4 S 0 3158 273.3049 D 44791 D On August 30, 2018, Ms. Ace adopted a 10b5-1 Plan. This 10b5-1 Plan allows the orderly disposition of shares owned by Ms. Ace. The shares set forth above were sold pursuant to the 10b5-1 Plan. This transaction was executed in multiple trades at prices ranging from $261.00 to $261.80. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. Included in this number are 24,715 unvested restricted stock units, 7,809 of which were granted on March 8, 2019 and shall vest through March 8, 2022, 10,031 of which were granted on March 8, 2018 and shall vest through March 8, 2021, and 6,875 of which were granted on August 22, 2016 and shall vest through August 22, 2020. This transaction was executed in multiple trades at prices ranging from $266.67 to $267.64. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. This transaction was executed in multiple trades at prices ranging from $267.745 to $268.545. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. This transaction was executed in multiple trades at prices ranging from $268.99 to $269.00. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. This transaction was executed in multiple trades at prices ranging from $270.01 to $271.00. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. This transaction was executed in multiple trades at prices ranging from $271.85 to $272.59. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. This transaction was executed in multiple trades at prices ranging from $272.89 to $273.71. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. By: Jereme Sylvain For: Heather S Ace 2020-03-10