U.S. stock markets have experienced significant declines, with the S&P 500 and Nasdaq both dropping sharply, influenced by disappointing earnings reports from major tech companies Microsoft and Meta. Despite beating third-quarter earnings expectations, concerns over their AI spending and the potential for rising costs have raised alarms among investors. The Dow Jones also fell by 250 points as these tech giants revived worries about the sustainability of their aggressive investments in artificial intelligence. Market analysts are now closely monitoring upcoming inflation data and the earnings of other major players, such as Apple and Amazon, which may further impact market sentiment.