DEXCOM INC — Director's Dealing 2014

Mar 14, 2014

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: DEXCOM INC (DXCM)
CIK: 0001093557
Period of Report: 2014-03-12

Reporting Person: LISTER JOHN (General Counsel, VP of HR)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2014-03-12	Common Stock	D	4562.0	$45.2216	Disposed	127950	Direct
2014-03-12	Common Stock	M	1750.0	$4.58	Acquired	129700	Direct
2014-03-12	Common Stock	S	1750.0	$45.01	Disposed	127950	Direct
2014-03-12	Common Stock	S	5999.0	$45.3819	Disposed	121951	Direct
2014-03-12	Common Stock	S	1409.0	$45.01	Disposed	120542	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2014-03-12	Non-Qualified Stock Option (right to buy)	$4.58	M	1750.0	Disposed	2019-05-19	Common Stock (1750)	Direct

Footnotes

F1: These shares were sold to cover the Company's tax withholding obligation that accrued in connection with the vesting of restricted stock units previously granted.

F2: Included in this number are 99,375 unvested restricted stock units, 65,000 of which were granted on March 8, 2014 and shall vest through March 8, 2017, 23,333 of which were granted on March 11, 2013 and shall vest through March 11, 2016, and 11,042 of which were granted on March 8, 2012 and shall vest through March 8, 2015.

F3: On December 11, 2013, Mr. Lister adopted a 10b5-1 Plan. This 10b5-1 Plan allows the orderly disposition of shares owned by Mr. Lister. The shares set forth above were sold pursuant to the 10b5-1 Plan.

F4: This transaction was executed in multiple trades at prices ranging from $45.38 to $45.39. 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 issurer full information regarding the number of shares and prices at which the transactions were effected.