Hedge fund billionaire Paul Tudor Jones, founder and CIO of Tudor Investment Corporation, has raised alarms about the state of financial markets in 2025, drawing pointed comparisons to the explosive tech-driven boom of 1999, while clarifying that today’s environment could be “so much more potentially explosive.” The reason why has to do with what the market veteran knows about how bull markets always play out.

Speaking to Andrew Ross Sorkin of the New York Times’ DealBook on CNBC’s Squawk Box ahead of the upcoming Robin Hood Foundation investor conference, Jones described today’s investment climate as uncannily similar to the one that preceded the 2000 dotcom bust.

“It feels exactly like 1999,” he said, implying that the market was acting like the famous Prince song with the lyrics, “Party like it’s 1999.” He urged investors to position themselves like it’s October 1999, when the Nasdaq doubled in a matter of months before collapsing, a pattern Jones sees as increasingly plausible today. The difference is that this could be even worse than the dotcom bust, he said.

Jones told Sorkin his concerns had to do with investor behavior in every bull market, specifically at the end, when the cliff is nearing and nobody is sure where it is.