Crown Castle’s customer map doubles as its landlord map

Crown Castle (CCI) has a two-company center of gravity: T-Mobile US (TMUS) and AT&T (T). They are customers and counterparties for tower leases and other agreements, and Crown Castle may eventually purchase some of those towers under disclosed options. The company’s disclosed relationship map is less a web than a very well-labeled triangle.

The customer concentration is the clearest starting point. In its filing for the three months ended March 31, 2026, Crown Castle said the three largest wireless carriers accounted for 93% of site rental revenue.

"Majority of our revenues from large wireless carriers For the three months ended March 31, 2026, approximately 93% of our site rental revenues were derived from T-Mobile, AT&T and Verizon Wireless."
Crown Castle / 10-Q / May 7, 2026

That group includes Verizon Communications (VZ), but T-Mobile and AT&T recur in nearly every other important part of the map. For the six months ended June 30, 2025, the same three carriers accounted for approximately 89% of site rental revenue.

"Majority of our revenues from large wireless carriers For the six months ended June 30, 2025, approximately 89% of our site rental revenues were derived from T-Mobile, AT&T and Verizon Wireless."
Crown Castle / 10-Q / Aug. 6, 2025

In plain English, Crown Castle discloses a carrier-heavy customer base, with the disclosed share at 93% in the more recent filing. Verizon is part of that revenue group. T-Mobile and AT&T are also the names attached to the physical infrastructure arrangements.

Crown Castle said approximately 55% of its towers are leased, subleased, or operated and managed under agreements with AT&T and T-Mobile, including agreements T-Mobile assumed in its merger with Sprint.

"Approximately 55 % of the Company's towers are leased or subleased or operated and managed under master leases, subleases, and other agreements with AT&T and T-Mobile (including those which T-Mobile assumed in its merger with Sprint)."
Crown Castle / 10-K / Feb. 23, 2026

So the same two carriers named in the revenue concentration also appear in the company’s master-lease and operating arrangements. That is the central dependency disclosed here: customers and counterparties are tightly interwoven.

The relationship also has a long-dated ownership angle. Crown Castle says it has the option to purchase leased and subleased towers from AT&T for approximately $4.2 billion at the ends of the relevant lease or sublease terms.

"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 such option is exercised, would be due…"
Crown Castle / 10-K / Feb. 23, 2026

T-Mobile appears on the other side of a similar option, though with a smaller disclosed aggregate payment and a stated window running from 2035 to 2049.

"The Company has the option to purchase the remainder of such towers from T-Mobile at the end of the respective terms for aggregate option payments of approximately $ 2.0 billion, which payments, if such option is exercised, would be due between 2035 and 2049."
Crown Castle / 10-K / Feb. 23, 2026

Together, those disclosed options total approximately $6.2 billion, if exercised. That is not a forecast of what Crown Castle will do. It is the size of the future purchase rights the company has disclosed, tied to the same two carriers already sitting at the center of its customer and lease map.

The rest of the disclosed network is more peripheral. AT&T names Crown Castle as a partner in AT&T’s filing. Anterix (ATEX) also calls Crown Castle a partner. SBA Communications (SBAC) names Crown Castle as a competitor, while Uniti Group (UNIT) calls it an investee. Crown Castle’s filing therefore points outward in four directions: two carrier relationships at the core, a tower competitor, a named investee, and partners identified by counterparties.

The shape is unusually specific. Crown Castle sells site access primarily to three large wireless carriers, but two of those carriers also appear as tower counterparties, operating partners, and potential sellers. The filing does not provide a verdict on that structure. It provides the names, percentages, agreements, and dollar amounts. That is the map.

These are relationships disclosed in SEC filings, mapped by jodie’s analytics. This is not investment advice.

Crown Castle’s customer map doubles as its landlord map

What Jodie is watching

Capital expenditures increased $257 million in the six months ended June 30, 2026 vs the comparable 2025 period, primarily for fiber and wireless network infrastructure investments.

Interest expense rose on higher average debt balances; watch quarterly interest expense and average debt balances for continued margin pressure.

Net cash used for investing activities was $313M for Q1 2026, up $58M (23%) year-over-year, driven primarily by increased discretionary capital expenditures including land purchases under towers.

Revolving Credit Facility unused interest rate reported at 4.755% (includes sustainability-linked spread reduction); higher blended swap rate and repayment increased weighted-average interest rate.