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

Major indexes sold off midday September 15 as the 10-year Treasury yield hit 4.99%, its highest level since 2007. The S&P 500 dropped 0.45%, the Nasdaq fell 0.73%, and the Dow declined 0.88%. Rising bond yields and oil prices combined to pressure equities across most sectors.

Semiconductor stocks bucked the broader selloff. NVDA, INTC, and MU posted slight gains as investors reassessed earlier concerns about AI scaling limitations. The moves suggest traders may be separating short-term technical concerns from longer-term AI infrastructure demand.

Cryptocurrency-related equities underperformed. COIN and HOOD declined ahead of Senate votes on cryptocurrency legislation, adding sector-specific pressure beyond the macro headwinds weighing on risk assets.

The bond market drove the session's tone. The approach of 5% on the 10-year yield raises fresh questions about equity valuations and borrowing costs, particularly for growth and technology names that had rallied earlier in the year.