Many fears of an AI bubble had hit a fever pitch at the start of this year when Chinese start-up DeepSeek released a competitive reasoning model.

Sam Altman says AI might be in a bubble—then touts trillions for OpenAI’s buildout. Call it the paradox powering Silicon Valley’s biggest spending spree.

Wall Street analysts are confident the artificial intelligence boom still has room to run. Even if Sam Altman, the OpenAI chief executive at the center of it all, appears less confident.