The hedge fund investor, who predicted the 2008 housing market crash, is making a huge bet against big tech.

The financial mind that predicted the biggest market crash in recent history is playing its hand once again. Michael Burry, the investor and hedge fund manager whose predictions about the 2008 housing market crash inspired the 2015 movie The Big Short, announced two put options totaling more than $1 billion against technology giants Nvidia and Palantir. A put option is a bet that speculates on a decline in a company’s share price and profits from it. Filings released Monday from the Securities Exchange Commission show that Burry’s hedge fund, Scion Asset Management, purchased $187 million and $912 million in bets against Nvidia and Palantir, respectively; Concerns about the actual valuations of AI companies are fueling rumors of a potential AI bubble.