DEXCOM INC — Director's Dealing 2016

May 19, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: DEXCOM INC (DXCM)
CIK: 0001093557
Period of Report: 2016-05-18

Reporting Person: VALDES JORGE A (CTO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-05-18	Common Stock	M	20000.0	$9.8	Acquired	111667	Direct
2016-05-18	Common Stock	S	20000.0	$61.7472	Disposed	91667	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2016-05-18	Non-Qualified Stock Option (right to buy)	$9.8	M	20000.0	Disposed	2020-03-12	Common Stock (20000)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	9588	Indirect

Footnotes

F1: This transaction was executed in multiple trades at prices ranging from $61.54 to $62.02. 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.

F2: Included in this number are 91,667 unvested restricted stock units, 38,000 of which were granted on March 8, 2016 and shall vest on March 8, 2019, 30,000 of which were granted on March 8, 2015 and shall vest through March 8, 2018 and 23,667 of which were granted on March 8, 2014 and shall vest through March 8, 2017.

F3: Shares are held by the Valdes-Lopez-Calleja Family Trust U/A/D 05/18/2011, with respect to which the reporting person is a trustee.