AMERICAN TOWER CORP /MA/ — Director's Dealing 2011

Mar 14, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AMERICAN TOWER CORP /MA/ (AMT)
CIK: 0001053507
Period of Report: 2011-03-10

Reporting Person: Sharma Amit (EVP, Asia)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-03-10	Class A Common Stock	M	4350	—	Acquired	10888	Direct
2011-03-10	Class A Common Stock	F	1151	$50.78	Disposed	9737	Direct
2011-03-10	Class A Common Stock	M	4403	—	Acquired	14140	Direct
2011-03-10	Class A Common Stock	F	1186	$50.78	Disposed	12954	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-03-10	Option to Purchase Class A Common Stock	$50.78	A	52601	Acquired	2021-03-10	Class A Common Stock (52601)	Direct
2011-03-10	Restricted Stock Units	$	A	17724	Acquired		Class A Common Stock (17724)	Direct
2011-03-10	Restricted Stock Units	$	M	4350	Disposed		Class A Common Stock (4350)	Direct
2011-03-10	Restricted Stock Units	$	M	4403	Disposed		Class A Common Stock (4403)	Direct

Footnotes

F1: This option was granted pursuant to the 2007 Equity Incentive Plan, and is exercisable in 25% cumulative annual increments beginning March 10, 2012.

F2: Each Restricted Stock Unit (RSU) respresents a contingent right to receive one share of Class A Common Stock.

F3: This RSU was granted pursuant to the 2007 Equity Incentive Plan, and vests in 25% cumulative annual increments beginning March 10, 2012.

F4: This RSU was granted on March 10, 2010 pursuant to the 2007 Equity Incentive Plan, and vests in 25% cumulative annual increments beginning March 10, 2011. This Form 4 reflects the vesting of this RSU on March 10, 2011 as to 25% of the original grant amount.

F5: This RSU was granted on March 10, 2009 pursuant to the 2007 Equity Incentive Plan, and vests in 25% cumulative annual increments beginning March 10, 2011. This Form 4 reflects the vesting of this RSU on March 10, 2011 as to 50% of the original grant amount.