What Comfort Systems USA, Inc. told the SEC could break it.

Direct purchase of commodities and finished products is 40-45% of average project cost; manufactured HVAC equipment, electrical switchgear and large power generators have lead-times often exceeding six months.

“We estimate that the direct purchase of commodities and finished products comprises between 40% and 45% of our average project cost. Orders for manufactured commercial HVAC equipment, electrical switch gear, and large application power generators have experienced the longest lead-times, and it is not uncommon for lead-times to be greater than six months.”

One (unnamed) customer represented 12.8%, 13.3% and 13.8% of consolidated revenue in 2025, 2024 and 2023, in the mechanical segment; loss could adversely affect results.

“For the years ended December 31, 2025, 2024, and 2023, one customer represented 12.8 %, 13.3 % and 13.8 % of consolidated revenue, respectively, and was included in our mechanical segment revenues.”

The Technology sector (largely data-center construction) was 45.0% of 2025 revenue, concentrating the business in one end-market whose capex cycle drives demand.

“Our distribution of revenue in 2025 by end-use sector was as follows: ​ ​ ​ ​ Technology ​ 45.0 % Manufacturing ​ ​ ​ 22.1 % Healthcare 8.9 % Education 7.3 % Government 5.0 % Office Buildings 5.0 % Retail, Restaurants and Entertainment 3.7 % Multi-Family and Residential 1.4 % Other 1.6 % Total 100.0 %”

Depends on third-party subcontractors for labor and suppliers for equipment/materials; nonperformance, labor shortages, or supplier failures could harm execution and profitability.

“We hire third-party subcontractors to perform work and depend on third-party suppliers to provide equipment and materials necessary to complete our projects. If we are unable to retain qualified subcontractors or suppliers, or if our subcontractors or suppliers do not perform as anticipated for any reason, our execution, reputation and profitability could be harmed.”

Changes in U.S. trade policy and tariffs (and trading-partner responses) could make it more difficult or costly to purchase materials and supplies, adversely affecting results.

“We cannot predict the full extent of new, extended, or changed trade policies, including tariffs, that may be made by the current or a future presidential administration or Congress, including whether existing tariff policies will be maintained or modified or if changes in the U.S. trade policy could result in reactions from U.S. trading partners, such as adopting responsive trade policies making it more difficult or costly for us to purchase materials or supplies.”