The Dow Jones Industrial Average plunged more than 300 points, or 0.7%, Tuesday as fears over an AI bubble shook the market and traders fretted that rate cuts from the Federal Reserve aren’t a sure thing. The S&P 500 had dipped 0.3% while the tech-heavy Nasdaq had fallen 0.6% as of about 1:15 p.m. ET as investors panicked over whether AI firms have been overvalued – extending a rocky tech rout into its third week. Shares in Nvidia fell 1.5%. The chipmaker is reporting its third-quarter results