AI Trade Falters in October as Broader Market Leaves Big Tech Behind

The artificial-intelligence boom that powered U.S. stocks through September has hit a wall in October, with Big Tech names like Nvidia, Microsoft, and Alphabet underperforming the rest of the market. After a historic comeback driven by AI enthusiasm, investors are now rotating into sectors that had lagged, such as energy, financials, and industrials. The shift suggests that the AI trade, which had been a key driver of the S&P 500’s gains, is losing momentum as valuations stretch and profit-taking sets in. For everyday investors, this rotation matters because it signals a potential broadening of the market rally beyond a handful of mega-cap tech stocks, reducing concentration risk but also raising questions about the durability of AI-driven earnings growth. With bond yields rising and economic data mixed, the coming weeks will test whether Big Tech can regain leadership or if the market’s new leaders will continue to carry the index.