8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
Date of Report (Date of Earliest Event Reported): January 23, 2018
AMERICAN TOWER CORPORATION
(Exact Name of Registrant as Specified in Charter)
Delaware		001-14195	65-0723837
(State or Other Jurisdiction of Incorporation)		(Commission File Number)	(IRS Employer Identification No.)
116 Huntington Avenue
Boston, Massachusetts 02116
(Address of Principal Executive Offices) (Zip Code)
(617) 375-7500
(Registrant's telephone number, including area code)
Not Applicable
(Former name or former address, if changed since last report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):
¨	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
¨	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
¨	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
¨	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).
Emerging growth company ¨
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 8.01Other Events.

On January 23, 2018, American Tower Corporation issued a press release (the “Press Release”) announcing an adjustment to the conversion rates for its 5.50% Mandatory Convertible Preferred Stock, Series B.

A copy of the Press Release is filed herewith as Exhibit 99.1.

Item 9.01Financial Statements and Exhibits.

(d)Exhibits

Exhibit No.	Description
99.1	Press Release, dated January 23, 2018.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

		AMERICAN TOWER CORPORATION
		(Registrant)
Date:	January 23, 2018	By:	/s/ Thomas A. Bartlett
			Thomas A. Bartlett
			Executive Vice President, Chief Financial Officer and Treasurer

EX-99.1

Exhibit 99.1

Contact: Igor Khislavsky

Director, Investor Relations

Telephone: (617) 375-7500

AMERICAN TOWER CORPORATION ANNOUNCES CONVERSION RATE ADJUSTMENT FOR 5.50% MANDATORY CONVERTIBLE PREFERRED STOCK, SERIES B

BOSTON, MASSACHUSETTS - January 23, 2018 - American Tower Corporation (NYSE: AMT) announced an adjustment to the conversion rates for its 5.50% Mandatory Convertible Preferred Stock, Series B (the “Series B Preferred Stock”). The adjustment to the conversion rates is being made pursuant to the Certificate of Designations establishing the Series B Preferred Stock (the “Certificate of Designations”) in connection with an early conversion on January 18, 2018 and in recognition of carried-forward adjustments relating to common stock cash dividends paid on July 14, 2017, October 17, 2017 and January 16, 2018, which adjustments were deferred and carried forward as permitted under the Certificate of Designations. The new Fixed Conversion Rates and Fundamental Change Conversion Rates (each as defined in the Certificate of Designations) are as set forth below:

Minimum Conversion Rate:          8.7420

Maximum Conversion Rate:        10.4905

Fundamental Change Conversion Rates:    

	Share Price on Effective Date
Effective Date	$49.14	$68.79	$88.45	$95.33	$108.10	$114.39	$127.76	$137.58	$147.41
March 3, 2015	9.4088	9.3580	9.0304	8.9123	8.7420	8.7420	8.7420	8.7420	8.7420
February 15, 2016	9.7842	9.7315	9.3357	9.1781	8.9247	8.8276	8.7420	8.7420	8.7420
February 15, 2017	10.1456	10.1483	9.7394	9.5199	9.1351	8.9864	8.7792	8.7420	8.7420
February 15, 2018	10.4905	10.4905	10.4905	10.4905	9.2506	8.7420	8.7420	8.7420	8.7420

About American Tower

American Tower, one of the largest global REITs, is a leading independent owner, operator and developer of multitenant communications real estate with a portfolio of approximately 149,000 communications sites. For more information about American Tower, please visit www.americantower.com.

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