On October 14, 2026, the S&P 500 index declined by 1.1%, while the Nasdaq composite fell by 1.9%. This marked the worst session for both indices since July, primarily driven by a sell-off in AI-related stocks.
The market reaction followed the release of September Consumer Price Index data, which showed a 0.6% month-over-month increase. Year-over-year, the CPI rose by 3.7%, exceeding the consensus estimate of 3.6%.
Investors expressed concerns that higher inflation could prompt the Federal Reserve to raise interest rates. This prospect negatively impacts companies with high capital expenditure requirements, such as those building data centers and purchasing chips.
Individual stock performance reflected this pressure: Nvidia and Broadcom shares each dropped 3.7%, while Advanced Micro Devices fell 6.1%. CoreWeave experienced a steeper decline of up to 15.9%.
The Philadelphia Semiconductor Index, representing a broader basket of chip manufacturers, also extended its losing streak. Rising Treasury yields further increased borrowing costs, intensifying scrutiny of AI infrastructure funding.
