US stocks tumbled on Tuesday, with the S&P 500 down 1.1%, the Nasdaq shedding 2.1%, and the Dow losing about 240 points, as investors grew increasingly uneasy over stretched valuations in AI-driven names and cautious outlooks from top Wall Street executives. Tech-heavy losses led the decline, with Palantir plunging 8.1% on valuation concerns despite beating earnings estimates, while Nvidia (-2.7%), AMD (-2.1%), and Oracle (-2.6%) also fell sharply. The pullback comes as the S&P 500’s forward P/E ratio climbed above 23, near its highest since 2000, heightening fears of a correction after months of concentrated gains in a handful of AI stocks. Comments from Goldman Sachs’ David Solomon and Morgan Stanley’s Ted Pick, warning of potential 10–20% market drawdowns, deepened the cautious sentiment. Tech, energy, and industrials led losses, while defensive consumer staples and financials outperformed. Berkshire Hathaway gained 3.3% as investors turned to safe plays amid the broader selloff.