'Big Short' investor warns AI boom rests on shaky foundation

Investor Steve Eisman, whose bet against the subprime mortgage market inspired the book and film "The Big Short," has raised concerns about the current structure of the AI boom. He argues that massive capital spending by tech giants on artificial intelligence infrastructure is effectively tied to the success of just two leading model developers — OpenAI and Anthropic. Should either company face serious technical, financial, or competitive setbacks, it could trigger a chain reaction across the entire supply chain, from chipmakers to cloud providers. Eisman notes that such risk concentration reminds him of past bubbles, when markets broadly believed in the infallibility of a narrow group of industry leaders. He suggests investors should pay close attention to portfolio diversification rather than betting solely on the continuation of the current AI rally.