Markets Drop as Wall Street Questions AI Valuations. Stock Futures Dive. Barron’sStocks making the biggest moves premarket: Uber, Sarepta, Palantir, Norwegian Cruise and more CNBCStock market today: Dow, S&P 500, Nasdaq futures sink as worries about frothy valuations run high Yahoo FinancePalantir Earnings ‘Best Results’ by Software Company Ever, CEO Says. Why the Stock Is Tumbling. Barron’sUS futures tumble after Wall Street banks warn of market pullback Reuters