What MasTec, Inc. told the SEC could break it.

AT&T was ~10% of MasTec's total consolidated revenue in 2025 (its single largest customer), and governmental entities were ~13% of revenue; reductions from these concentrated sources could materially affect results.

“For the year ended December 31, 2025, AT&T represented approximately 10 % of the Company's total consolidated revenue. ... Revenue from governmental entities totaled approximately 13 % of total revenue for both the years ended December 31, 2025 and 2024, and 11 % for the year ended December 31, 2023, substantially all of which was derived from its U.S. operations.”

MasTec's revenue depends on customer capital projects; factors outside its control could result in fewer projects than anticipated or delays in project timing, reducing demand for its services and materially affecting results, cash flows and liquidity.

“All of the above factors could result in fewer projects than anticipated or a delay in the timing of these projects, which could negatively affect demand for our services and have a material adverse effect on our results of operations, cash flows and liquidity.”

2025 US trade/tariff actions against Canada, Mexico, the EU, Japan, Germany and China (plus retaliatory measures) raised the cost of importing construction materials — including steel, concrete and solar panels — and disrupted MasTec's supply chains.

“During the year ended December 31, 2025, the U.S. government announced significant trade policy and tariff actions on imports from a broad set of countries, including Canada, Mexico, European Union member states, Japan, Germany and China, in response to which many countries announced retaliatory trade actions, including tariffs on U.S. exports or bans by foreign countries on certain of their exports. These actions have increased the cost of importing certain construction materials into the U.S., including steel, concrete and solar panels, and have caused disruption and uncertainty to both international trade and supply chains.”