
	Basis of Presentation

The consolidated financial statements include the accounts of Crown Castle International Corp. ("CCIC") and its majority and wholly-owned subsidiaries, collectively referred to herein as the "Company." All significant intercompany balances and transactions have been eliminated in consolidation. As used herein, the term "including" and any variation thereof, means "including without limitation." The use of the word "or" herein is not exclusive.

The Company owns, operates, and leases shared wireless infrastructure, including: (1) towers and other structures, such as rooftops (collectively, "towers"), (2) distributed antenna systems ("DAS"), a type of small cell network ("small cells"), and (3) interests in land under third party towers in various forms (collectively, "third party land interests") (collectively, "wireless infrastructure"). The Company conducts operations through subsidiaries of Crown Castle Operating Company ("CCOC"), including (1) certain subsidiaries which operate wireless infrastructure portfolios in the United States, including Puerto Rico ("U.S." or "CCUSA") and (2) a 77.6% owned subsidiary that operates towers in Australia (referred to as "CCAL"). The Company's core business is providing access, including space or capacity, to (1) its towers, including approximately 39,600 towers (or 96% of the Company's total towers) in CCUSA and approximately 1,700 towers (or 4% of the Company's total towers) in CCAL, and to a lesser extent, to (2) its small cells, and (3) third party land interests to wireless communications companies via long-term contracts in various forms, including licenses, subleases and lease agreements (collectively, "contracts").

Approximately 53% of the Company's towers are leased or subleased or operated and managed under master leases,subleases, or other agreements with Sprint, T-Mobile, and AT&T. The Company has the option to purchase these towers at the end of their respective lease terms; such options are not firm commitments and are not required. Additional information concerning these towers is as follows:


◦	Approximately 16% of the Company's towers are leased or subleased or operated and managed for an initial period of 32 years (through May 2037) under master leases, subleases, or other agreements with Sprint. The Company has the option to purchase in 2037 all (but not less than all) of the leased and subleased Sprint towers from Sprint for approximately $2.3 billion.

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Approximately 15% of the Company's towers are leased or subleased or operated and managed under a master prepaid lease or other related agreements with T-Mobile for a weighted-average term of approximately 28 years, weighted on site rental gross margin. The Company has the option to purchase the leased and subleased towers from T-Mobile at the end of the respective lease or sublease terms for aggregate option payments of approximately $2.0 billion, which payments, if exercised would be due between 2035 and 2049. In addition, through that acquisition, there are another approximately 1% of the Company's towers subject to a lease and sublease or other related arrangements with AT&T. The Company has the option to purchase these towers that it does not otherwise already own at the end of their respective lease terms for aggregate option payments of up to approximately $405 million, which payments, if exercised, would be due between 2018 and 2032 (less than $10 million would be due before 2025).

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Approximately 22% of the Company's towers are leased or subleased or operated and managed under a master prepaid lease or other related agreements with AT&T for a weighted-average term of approximately 28 years, weighted on site rental gross margin. The Company has the option to purchase the leased and subleased towers from AT&T at the end of the respective lease or sublease terms for aggregate option payments of approximately $4.2 billion, which payments, if exercised, would be due between 2032 and 2048.

As part of CCUSA's effort to provide comprehensive wireless infrastructure solutions, it offers certain network services relating to it wireless infrastructure, consisting of (1) customer equipment installation or subsequent augmentations (collectively, "installation services") and (2) the following additional site development services relating to existing or new antenna installations on its wireless infrastructure: site acquisition, architectural and engineering, zoning or permitting, other construction, or network development related services.

The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.