Ray Dalio, the billionaire founder of Bridgewater Associates, has issued one of his most forceful warnings yet about the current market environment. During an appearance on The Diary of a CEO podcast with Steven Bartlett, he argued that artificial-intelligence enthusiasm has pushed asset prices into bubble territory reminiscent of 1929 and 2000. His warning arrives just as markets prepare to test his thesis in real time: SpaceX has already gone public in the largest IPO ever, and Anthropic and OpenAI are moving toward trillion-dollar valuations—precisely the kind of speculative issuance surge that market historians treat as a bubble’s clearest warning sign.
Bartlett opened by referencing a prior guest, Jeremy Grantham, who told the show that markets are staring down “the biggest investment bubble in American history.” Dalio’s response was direct: “He’s right,” he said.
That call is consistent with Grantham’s long track record. The cofounder of GMO called the Japanese asset bubble before it collapsed in the early 1990s and the dotcom bubble before it burst. In September 2007, he wrote that U.S. housing was in “genuine bubble territory” months before the Great Financial Crisis, at a time when even the Federal Reserve was dismissing bubble talk.
A “bubble within a bubble”
When Grantham appeared on the podcast earlier in the year, he laid out the framework underpinning his current AI call: a “bubble within a bubble.” The original super-bubble was already inflating dangerously through 2021, he said, and it even cracked—with the S&P 500 falling roughly 25% from January through October 2022—before ChatGPT’s arrival reversed the decline. “The day after Chat came out, the Mag Seven lifted the market on its broad shoulders and staggered forward,” he said. AI did not fix the underlying overvaluation, in his view; it deferred it while making it larger.
In a January 2026 paper with financial historian Edward Chancellor, Grantham found that the market’s price/book ratio and cyclically adjusted earnings multiples were at extremes surpassed only in 1929, 1972, 1999–2000, and 202
Source: MSN News