Stock Market Midday, Oct. 15: Markets Mixed as AI Sell-Off Continues

Markets showed mixed performance on October 15, 2026, as concerns over AI debt and capital costs triggered a semiconductor sell-off. The Dow rose 0.82% while the Nasdaq fell 0.36%. Inflation data and CoreWeave's elevated bond yields (15%) spooked investors, though Nvidia's CEO attempted to restore confidence. AI stocks comprise 40% of the S&P 500, making diversification critical for investors.