2018 Guide to Effective Proxies

6 TH EDITION | GUIDE TO EFFECTIVE PROXIES 318 PROXY STATEMENT SUMMARY Asset Expansion in Legacy and New Markets We expect our 2017 global portfolio expansion efforts in our legacy and new markets to further extend our ability to generate compelling long-term sustainable growth. These transactions included: • Launch of operations in two new markets through our acquisitions of (i) FPS Towers SAS (FPS), which owned or operated nearly 2,500 wireless tower sites in France and (ii) communications sites in Paraguay from Tigo Paraguay; • Continued expansion of our communications site portfolio in existing markets through the construction of nearly 2,000 sites and the acquisition of over 1,600 sites; • Acquisition of urban telecommunications assets in Mexico, including more than 50,000 concrete poles and approximately 2,100 route miles of fiber; and • Entry into definitive agreements with Idea Cellular Limited (Idea) and Vodafone India Limited (Vodafone), through which we have added approximately 10,000 communications sites and expect to add approximately 10,000 additional communications sites to our existing portfolio in India. CEO’s Track Record of Success Mr. Taiclet has served as our CEO since 2003. Under his stewardship, American Tower has continued to deliver solid performance while substantially growing its operations and simultaneously returning cash to stockholders. Below are some of the key highlights relating to Mr. Taiclet’s tenure with the Company (beginning at the end of 2003 through December 31, 2017): • Completed several transformative transactions, including the acquisition of SpectraSite, Inc. in 2005, the acquisition of MIP Tower Holdings LLC in 2013, the transaction with Verizon Communications Inc. in 2015, the acquisition of Viom Networks Limited (Viom) in 2016 and the acquisition of FPS in 2017, all of which strategically positioned the Company as a global leader in multitenant communications real estate; • Exceeded our long-term aspirational goal for growth over a ten-year horizon by quadrupling assets and certain financial metrics ahead of schedule; • Increased our asset base by a factor of ten, from 15,000 communications sites to over 150,000 communications sites; • Expanded our geographic footprint from three countries to 16 countries, while diversifying our tenant base with well-capitalized global mobile network operators; and • Returned excess capital to stockholders, including through our stock repurchase program and distributions to preferred and common stockholders in the aggregate of approximately $9.4 billion, including the dividend paid in January 2018. Executive Pay Mix CHIEF EXECUTIVE OFFICER – TARGET COMPENSATION AVERAGE OF OTHER FOUR NEOS– TARGET COMPENSATION 91% Variable (Annual Incentive Award + Equity Awards) 9% Base Salary 80% Long-Term Incentive (EquityAwards) 11% Annual Incentive Award 87% Variable (Annual Incentive Award + Equity Awards) 13% Base Salary 75% Long-Term Incentive (EquityAwards) 12% Annual Incentive Award AMERICAN TOWER CORPORATION 2018 PROXY STATEMENT 5 Total of 02 pages in section AMERICAN TOWER CORPORATION