Why US Utility Stocks Are Falling After the AI Power Surge

The artificial-intelligence boom’s promise of runaway electricity demand has jolted shares of US power companies to all-time highs. But those generators and utilities are now learning that the hype comes with an edge: Investors won’t wait forever for results.

Companies that recently hit record valuations are returning to earth as investors realize the massive data-center deals they’d banked on are actually smaller, or slower, than expected.