The GMO cofounder called the Japanese asset bubble before it collapsed in the early 1990s and the dotcom bubble before it burst. He’s identified surging stock issuance as one of the two primary forces that “prick” a bubble, alongside rising interest rates. His core distinction is between wealth and money: “Wealth is not the same as money,” he said. You have to sell the wealth to get money because you can only spend money.” He stressed a bubble is “a degree thing” rather than binary, pointing to unsophisticated investors piling into leveraged bets, including leveraged ETFs tracking the stock market.