What Crown Castle Inc. told the SEC could break it.

Crown Castle derives ~90% of its 2025 site rental revenue from just three wireless carriers (T-Mobile, AT&T, Verizon); carrier consolidation already cost ~$200M in 2025 from T-Mobile/Sprint non-renewals, illustrating the severity of this concentration.

“For the year ended December 31, 2025, approximately 90% of our site rental revenues were derived from T-Mobile, AT&T and Verizon Wireless. See "Item 1A. Risk Factors" and note 15 to our consolidated financial statements for a further discussion of our largest customers. ◦ During 2025, our site rental revenues decreased approximately $200 million as a result of non-renewals related to the network consolidation of T-Mobile and Sprint.”

Crown Castle's towers are regulated by the FCC and FAA — governing siting, construction, modification, lighting, marking, and registration — and failure to comply could bring fines or loss of rights to conduct parts of its business.

“Both the FCC and the FAA regulate towers used for wireless communications, radio, or television broadcasting. Such regulations control the siting, construction, modification, lighting, and marking of towers and may, depending on the characteristics of particular towers, require the registration of tower facilities with the FCC and the issuance of determinations confirming no hazard to air traffic.”

Crown Castle derives ~60% of its towers Adjusted Site Rental Gross Margin from towers on land it leases, subleases, manages, or licenses (only ~40% on owned land/easements), making it dependent on landlords and ground-lease renewals.

“We derive approximately 40% of our towers Adjusted Site Rental Gross Margin from towers located on land that we own, including through fee interests and perpetual easements, and we derive approximately 60% of our towers Adjusted Site Rental Gross Margin from towers located on land that we lease, sublease, manage or license.”