AMERICAN TOWER CORP /MA/ — Director's Dealing 2012

Oct 3, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: AMERICAN TOWER CORP /MA/ (AMT)
CIK: 0001053507
Period of Report: 2012-10-01

Reporting Person: HESS WILLIAM H (EVP, Int'l. Operations)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-10-01	Common Stock	M	8125	$28.39	Acquired	28902	Direct
2012-10-01	Common Stock	M	1875	$37.70	Acquired	30777	Direct
2012-10-01	Common Stock	S	6900	$71.19	Disposed	23877	Direct
2012-10-01	Common Stock	S	3100	$72.02	Disposed	20777	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-10-01	Option to Purchase Common Stock	$28.39	M	8125	Disposed	2019-03-10	Common Stock (8125)	Direct
2012-10-01	Option to Purchase Common Stock	$37.70	M	1875	Disposed	2018-03-17	Common Stock (1875)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	5095	Indirect

Footnotes

F1: The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan.

F2: Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $70.73 to $71.68 per share.

F3: Represents the weighted average price of shares sold in multiple same-day transactions at prices ranging from $71.74 to $72.26 per share.

F4: This option was granted pursuant to the 2007 Equity Incentive Plan and is exercisable in 25% cumulative annual increments beginning March 10, 2010.

F5: This option was granted pursuant to the 2007 Equity Incentive Plan and is exercisable in 25% cumulative annual increments beginning March 17, 2009.