Comfort Systems USA, Inc.

The filings show a company whose revenue base has expanded quickly. Annual revenue grew from $2.18 billion in 2018 to $9.1 billion in 2025, and the $7.03 billion reported for 2024 implies roughly 29% growth into 2025. The first-quarter 2026 figures extend that pattern, with operating income of $485.7 million compared with $209.1 million a year earlier, and selling, general and administrative expenses falling to 9.4% of revenue from 10.6%, which management attributes to operating leverage. Several items deserve a closer read. The effective tax rate rose to 23.2% from 18.6%, mainly because of $12.7 million of net state income taxes, and the prior-year rate had been helped by $8.9 million of interest income on a federal overpayment. Earn-out expense tied to the Feyen Zylstra acquisition rose to $10.4 million from $3.8 million, reflecting higher projected earnings at that business. Interest income rose 99.5% to $8.5 million, which the company ties to a larger average cash balance. Government projects were 5.0% of 2025 revenue, a smaller exposure than the technology-sector concentration now visible in segment results. Management expects high ongoing demand and solid earnings for the rest of 2026, while also citing labor cost pressure, supply delays, and possible recession risk. Readers may want to look at how backlog converts into revenue and margin over the next two to four quarters, since the company itself describes backlog as indicating revenue direction over only the next six to 12 months.

Catalyst.Management attributes growth to strong market conditions and a larger backlog, with demand especially strong in the technology sector, particularly data centers. First-quarter 2026 revenue rose 56.5% to $2.87 billion from $1.83 billion, including a 51.5% same-store increase. Mechanical segment revenue grew 47.0% to $2.06 billion, led by technology-sector activity at a Texas operation ($181.4 million) and an Indiana operation ($137.7 million). Electrical segment revenue rose 87.5% to $804.7 million, with a Texas electrical operation contributing a $200.9 million same-store increase. Backlog reached $12.45 billion at March 31, 2026, up 80.8% from $6.89 billion a year earlier. Gross margin widened to 26.3% from 22.0%, and net income rose to $370.4 million from $169.3 million.

Hidden risk.The growth rests on a narrow set of drivers and on items management itself describes as uncertain. Management says backlog has limited predictive value and that it reflects only a portion of future revenue, while the risk factors state that backlog can be adjusted or cancelled and may not produce profitable revenue. The risk factors also warn that a limited number of customers have in the past accounted for a large share of revenue. Part of the margin gain came from favorable developments on projects nearing completion, including about $43.1 million of change orders, equal to roughly 5.7% of first-quarter gross profit. Because the company bears cost-overrun risk on most contracts, rising labor costs and intermittent supply shortages could compress margins on the same projects now driving results.