PHLX Semiconductor Index Suffers Second-Largest One-Day Drop

The PHLX Semiconductor Index experienced its second-largest one-day decline on record on November 5, 2026, falling 12.25% to close at 9,011.14. This represents the steepest drop for the index since the March 2020 COVID-19 crash. The selloff erased an estimated $1.5 trillion in market value for chipmakers and contributed to a broader S&P 500 decline of approximately $3 trillion.

Micron Technology and Lam Research were the hardest hit, with both companies seeing their stock prices sink roughly 17%. NVIDIA fell 9.26%. The disparity in these losses suggests that investors are pricing in a slowdown for plant and equipment capital expenditure rather than a decline in current demand for artificial intelligence.

Market analysts attribute the crash to institutional selling, hedge funds locking in gains from top performers, and concerns that Democratic wins in Congress will lead to tougher AI regulation. Investors are now focusing on NVIDIA's earnings report scheduled for November 17 to determine if the selloff was a temporary correction or a fundamental unwind of the sector.