X0306 4 2018-09-11 0 0001093557 DEXCOM INC DXCM 0001612451 Blackford Quentin S. 6340 SEQUENCE DRIVE SAN DIEGO CA 92121 0 1 0 0 EVP, CFO, PFO & PAO Common Stock 2018-09-11 4 S 0 2100 145.2298 D 93471 D Common Stock 2018-09-11 4 S 0 1200 146.1483 D 92271 D Common Stock 2018-09-11 4 S 0 1460 147.4065 D 90811 D Common Stock 2018-09-11 4 S 0 3680 148.2211 D 87131 D On August 7, 2018, Mr. Blackford adopted a 10b5-1 Plan. This 10b5-1 Plan allows the orderly disposition of shares owned by Mr. Blackford. The shares set forth above were sold pursuant to the 10b5-1 Plan. This transaction was executed in multiple trades at prices ranging from $144.54 to $145.50. 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 85,271 unvested restricted stock units, 38,502 of which were granted on March 8, 2018 and shall vest through March 8, 2021 and 46,769 of which were granted on September 7, 2017 and shall vest through September 7, 2021. This transaction was executed in multiple trades at prices ranging from $145.68 to $146.58. 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 $146.75 to $147.74. 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 $147.75 to $148.44. 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: Kevin Sun For: Quentin S. Blackford 2018-09-13