Crown Castle owns and operates approximately 40,000 cell towers across the U.S., and its core business is leasing space on those towers to wireless carriers. Carriers mount antennas and radio equipment on Crown Castle's towers to run their mobile networks. T-Mobile, AT&T, and Verizon together account for roughly 90% of site rental revenues, which represent about 95% of total revenues. Crown Castle is structured as a REIT. The tower leasing model is highly attractive: tenant contracts run five to fifteen years with annual rent escalators, providing predictable, growing cash flows, and roughly 80% of any given year's organic growth is already contracted. Because each tower has largely fixed costs — primarily ground lease payments, which make up about 75% of site rental operating costs — adding tenants drives revenue at very high incremental margins. The average tower has about 2.4 tenants. Crown Castle is in the process of selling its Fiber segment (small cells and fiber solutions) to EQT and Zayo for $8.5B, with close expected in the first half of 2026. Post-close, Crown Castle will be a pure-play U.S. tower company. Crown Castle plans to use roughly $7B of sale proceeds to repay debt and approximately $1B for share buybacks, targeting leverage of 6.0–6.5x EBITDA. The company maintains an annualized dividend of $4.25/share, targeting a payout of 75%–80% of AFFO over time.