DEXCOM INC — Director's Dealing 2018

May 11, 2018

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: DEXCOM INC (DXCM)
CIK: 0001093557
Period of Report: 2018-05-09

Reporting Person: SAYER KEVIN R (Director, President & CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2018-05-09	Common Stock	M	31464	$7.63	Acquired	366635	Direct
2018-05-09	Common Stock	S	17245	$84.3718	Disposed	349390	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2018-05-09	Non-Qualified Stock Option (right to buy)	$7.63	M	31464	Disposed	2018-05-19	Common Stock (31464)	Direct

Footnotes

F1: The reporting person exercised options that were granted in 2008 and scheduled to expire on May 19, 2018. He sold shares to pay the exercise price and associated taxes on the options, and retained the net number of shares.

F2: This transaction was executed in multiple trades at prices ranging from $84.29 to $84.67. 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.

F3: Included in this number are 164,731 unvested restricted stock units, 80,545 of which were granted on March 8, 2018 and shall vest through March 8, 2021, 54,186 of which were granted on March 8, 2017 and shall vest through March 8, 2020, 30,000 of which were granted on March 8, 2016 and shall vest through March 8, 2019.