Comfort Systems USA

The company's order book for future work hit 14.06 billion dollars last quarter, up 73 percent from a year earlier. Quarterly revenue crossed 3 billion dollars for the first time, growing 50 percent year over year, and profit margins are expanding at the same time instead of shrinking as the business scales.

Instead of assembling everything on a crowded job site, Comfort Systems builds sections of cooling and electrical systems in its own manufacturing facilities and trucks them in ready to install. That cuts delays for customers racing to open data centers on schedule, and it is a real edge that competitors without this factory capacity cannot easily copy.

Around 6 in 10 dollars of revenue now comes from technology and data center customers, up sharply from just a few years ago. If big tech companies slow their data center spending, Comfort Systems would feel it faster and harder than a more diversified contractor.

Management itself has pointed to finding enough skilled electricians and building enough factory space as real constraints on growth. The stock has already climbed sharply, so the company needs years of continued strong execution, not just solid results, to justify where it trades today.