Comfort Systems USA shares surge 6.58% after-hours as S&P 500 inclusion and AI infrastructure backlog drive optimism.

Comfort Systems USA surged 6.58% in after-hours trading, driven by its upcoming inclusion in the S&P 500 index, robust backlog growth tied to AI infrastructure and healthcare projects, and leadership changes. The company’s strong operating results, dividend raises, and analyst upgrades further reinforced the bull case. UBS and other firms raised price targets, citing confidence in its long-term backlog and data center demand. Institutional buying and index-driven inflows amplified the move, aligning with the stock’s 52-week high and elevated valuation.