AMT: 10-Q financial filing

amt-20260930 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One): ☒ Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. For the quarterly period ended September 30, 2026 . ☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. Commission File Number: 001-14195 AMERICAN TOWER CORPORATION (Exact name of registrant as specified in its charter) Delaware 65-0723837 (State or other jurisdiction of Incorporation or Organization) (I.R.S. Employer Identification No.) 222 Berkeley Street Boston , Massachusetts 02116 (Address of principal executive offices) Telephone Number ( 617 ) 375-7500 (Registrant’s telephone number, including area code) Securities registered pursuant to Section 12(b) of the Act: Title of each Class Trading Symbol(s) Name of exchange on which registered Common Stock, $0.01 par value AMT New York Stock Exchange 0.450% Senior Notes due 2027 AMT 27C New York Stock Exchange 0.400% Senior Notes due 2027 AMT 27D New York Stock Exchange 4.125% Senior Notes due 2027 AMT 27F New York Stock Exchange 0.500% Senior Notes due 2028 AMT 28A New York Stock Exchange 0.875% Senior Notes due 2029 AMT 29B New York Stock Exchange 0.950% Senior Notes due 2030 AMT 30C New York Stock Exchange 3.900% Senior Notes due 2030 AMT 30D New York Stock Exchange 4.625% Senior Notes due 2031 AMT 31B New York Stock Exchange 1.000% Senior Notes due 2032 AMT 32 New York Stock Exchange 3.625% Senior Notes due 2032 AMT 32B New York Stock Exchange 1.250% Senior Notes due 2033 AMT 33 New York Stock Exchange 4.000% Senior Notes due 2033 AMT 33D New York Stock Exchange 4.100% Senior Notes due 2034 AMT 34A New York Stock Exchange Indicate by check mark whether the registrant (1) has filed a