Veteran investor Jeremy Grantham says the U.S. stock market is the most expensive in American history, driven by the artificial intelligence boom, and could eventually lead to a historic decline. He told CNBC that the market capitalization to GDP ratio is estimated at 235%, well above the level Warren Buffett once warned was playing with fire. Grantham compared the current environment to the 2000 tech bubble and noted that Amazon shares fell 92% after that bubble before eventually dominating. He also pointed to SpaceX's recent public debut and roughly $2 trillion valuation as a sign of extreme market enthusiasm that historians may view as one of the defining peaks of all time.
Space Exploration Technologies Corp. Class A Common StockCited as a sign of extreme market enthusiasm with its recent public debut and high valuation, but no direct impact on the company itself.
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