US stock market crash: Chip stocks extend sell-off, AMD, Arm, Qualcomm and Sandisk plunge up to 17%; Nasdaq down 6%

US semiconductor stocks suffered a renewed sell-off, with AMD, Arm, Qualcomm, Micron and Sandisk falling 9% to 17% amid concern that Democratic gains in Congress could lead to tighter restrictions on AI infrastructure and data-centre expansion. Qualcomm dropped 14% after its profit forecast disappointed, while Arm fell 15% after revenue guidance failed to meet expectations; Nvidia lost 9% and Intel 10%. The PHLX Semiconductor Index fell 9.7%, the S&P 500 declined 4%, the Nasdaq 100 dropped as much as 6.5%, and the Dow fell 3%.