US equity markets ended sharply lower on December 12 as renewed concerns over an artificial intelligence-driven valuation bubble weighed heavily on technology stocks. The Nasdaq Composite led declines, falling 1.7 percent, while the S&P 500 dropped 1.1 percent and the Dow Jones Industrial Average slipped 0.5 percent after briefly touching an intraday record. Weak earnings updates from Oracle and Broadcom intensified selling pressure across chip and cloud related names, with several semiconductor stocks posting steep losses.