Comfort Systems beat everything, refused the AI labs, and the stock fell 9%

Bill George helped found Comfort Systems USA▲+8.10% — Comfort Systems USA, up 8.10 percent today in 1997 and has spent three decades deciding which jobs the mechanical contractor takes ¹. On the third-quarter earnings call Friday↗, with the company printing its best numbers ever, he said the newest AI money has not cleared the bar: "we haven't yet reached terms where we're willing to accept business from these people" ¹.

A record quarter, priced down 9 percent

The results landed Wednesday: revenue of $3.77 billion for Q3 2026, up 54 percent year over year, with net income of $489 million, or $13.91 per diluted share↗, both beating FactSet▼−3.03% — FactSet, down 3.03 percent today estimates of $3.40 billion and $12.85 ³⁵. Free cash flow hit $806 million in the quarter and roughly $2 billion year to date ⁵. Backlog reached a record $17.81 billion, up 90 percent year over year and up $3.8 billion sequentially, the eighth straight increase ²⁵.

Shares fell about 8 to 9 percent on October 23 anyway ⁴. TradingKey attributes the drop to withheld forward guidance, the CFO retirement, counter-seasonal margin compression (Electrical gross margin slipped to 24.3 percent from 26.2 percent a year earlier) and roughly $43.2 million of insider sales documented in SEC filings↗ in recent months ⁴. Analysts trimmed targets the same morning: KeyBanc to $1,979 from $2,125, Goldman▲+2.39% — Goldman, up 2.39 percent today to $1,895 ³.

The refusal, and the terms behind it

The friction point is modular construction: factory-built mechanical blocks shipped to data center sites. President Trent McKenna said Comfort is building product now for a frontier AI lab and colocation providers, but will not call any of it "programmatic," the company's label for long-term committed volume. Programmatic customers typically sign five-year commitments↗ before Comfort spends heavily to build capacity for them ¹².

Asked how Comfort vets newer data center customers, George said some entrants taking large modular books appear to be agreeing to terms where they are "banking some people," and added: "if we lose work on that basis, we don't mind it" ¹.

Comfort sticks with two big customers, one of 20 years, who want more than the company can supply; diverting would trade "a sure thing" for "a mystery" ¹. Modular capacity is set to exceed 4 million square feet by end-2026 and about 6 million by end-2027, all of it tied to existing committed customers ¹².

What investors must weigh

George retires shortly after the 2026 annual report↗; Chief Accounting Officer Julie Shaeff succeeds him ¹⁶. Backlog duration has meanwhile stretched to 18 to 24 months from about 9 a decade ago ².

Investors now hold a clean split: the bull case is a labor-constrained contractor with pricing power and committed hyperscaler demand; the bear case is a firm refusing its fastest-growing customer class, guiding vaguely, with insiders selling. Management is underwriting counterparty risk, not just revenue. Which side of the ledger that discipline lands on is the next reading: the 2026 annual report, filed alongside a new CFO's first look at the books.