The Nasdaq-100 fell after Google-parent Alphabet reported disappointing Q3 results, causing its stock to drop over 10% in pre-market trading. The company showed slower search advertising growth and a significant negative free cash flow, which raised investor concerns about the high cost of artificial intelligence development. While Microsoft posted strong results, Alphabet's report has created broader anxiety about the profitability and timeline for monetizing large AI investments across the mega-cap tech sector.