Comfort Systems is hard at work putting together the components of America’s next great computing build-out somewhere outside of Houston on a stretch of industrial land where the wind keeps the steel buildings cooler than the asphalt. Not on some ostentatious campus in Silicon Valley. Workers assemble cooling units in prefabricated, modular bays that will eventually be transported to a data center powered by a small city’s worth of electricity.
It’s an unglamorous business, which is precisely why the stock’s increase is so peculiar. Over the previous year, FIX has increased by about 374%. Depending on when you check, it has increased by more than 77% so far this year. As you watch this happen, you get the impression that a plumbing contractor has experienced something that is typically reserved for chipmakers.
Only a portion of it can be explained by the first quarter’s numbers. Revenue climbed 56.5% to $2.87 billion. Earnings per share exceeded analyst estimates by 55%, more than doubling to $10.51. The gross margin increased to 26.3% from 22% the previous year, which is the kind of change that makes a mechanical contractor reevaluate the line. Additionally, the backlog—that silent leading indicator that no marketing team ever boasts about loudly enough—reached $12.45 billion. It was $6.89 billion a year prior. In this industry, doubling a backlog in a year is abnormal. It simply isn’t.
Even though the scope of it is still being taken in, the motivation behind it is no secret. Over half of the company’s revenue now comes from data centers, with industrial work accounting for nearly three-quarters of the total. The entire mechanical and electrical contracting industry has been forced to reconsider capacity as hyperscalers like Amazon, Microsoft, and Alphabet are investing heavily in AI infrastructure. With its army of about 18,000 workers and its modular construction facilities, Comfort Systems is right where the money is going. By year’s end, management anticipates that modular capacity will reach four million square feet. They recently purchased a second assembly plant in Texas. They make more plans.
It’s difficult to ignore the fact that Caterpillar used the same pick-and-shovel reasoning in previous industrial cycles. Cooling, electrical distribution, piping, and controls are all necessary for the AI boom. It all needs to be installed by someone. Before, there were similar questions about whether the demand was genuine for Tesla. Although the comparison quickly breaks down, there is a slight echo of that here: FIX has increased its dividend for 14 years in a row and been profitable for 27. It’s not a story stock. It’s a contractor who just so happens to be in the right decade.
Even so, the valuation is beginning to seem uneasy. The stock is trading at about 42 times forward earnings, which is significantly higher than its own one-year median of roughly 33 and significantly higher than the building-products industry average of about 29. Insiders have been selling; CEO Brian Lane sold roughly 11,000 shares for about $22 million in a single transaction, and over the last ninety days, insider sales have totaled nearly $79 million. That’s not necessarily a bad thing. Owners of large stocks that have performed similarly to FIX typically trim. However, it makes noise. It’s possible that the easy money has already been made, leaving only execution risk disguised as opportunity.
For the time being, Wall Street is largely unaffected by the concern. In just thirty days, consensus 2026 EPS estimates have increased from $35.06 to $43.03, with six out of eight analysts rating FIX as a Strong Buy. It is anticipated that revenue will increase by roughly 30%. With more than $1 billion in cash and just $39 million in debt at the end of the quarter, the company has the kind of balance sheet that can withstand a slowdown if one occurs.
The market’s continued willingness to pay premium multiples for an industrial product may be more important in determining whether FIX has more room to grow than the AI thesis, which appears to be stable for at least a few more years. There’s a sense that while the stock isn’t finished, the subsequent leg won’t be as forgiving of those who arrive late. The work is being done by the company. Whether the price has surpassed even that is the question.
