Stock Market Midday, Sept. 15: Stocks Slide on AI and Bond Jitters

Major stock indexes declined on September 15, 2026, as concerns over AI scaling pressures and rising bond yields weighed on markets. The S&P 500 fell 0.45%, the Nasdaq dropped 0.73%, and the Dow declined 0.88%. The 10-year Treasury yield reached 4.99%, its highest level since 2007. While some semiconductor stocks like Nvidia, Intel, and Micron gained slightly as investors reassessed AI concerns, cryptocurrency stocks fell ahead of Senate legislation votes. High treasury yields and rising oil prices compounded market weakness.