US tech stocks extended their selloff on Thursday, with the Nasdaq Composite plunging 3.3% as investors fled AI and semiconductor shares following Democrats' sweep of Congress in the midterm elections. The S&P 500 dropped 1.9%, while the Dow Jones Industrial Average fell 489 points (0.9%). The Philadelphia Semiconductor Index tumbled 8%, hitting its lowest level since April 20. Chip and data-center-related stocks bore the brunt of the decline for a second consecutive session. AMD fell 12%, Micron Technology dropped 9%, SK Hynix declined 8.8%, and Nvidia slipped 5%. The Nasdaq Composite is now down more than 10% from its record closing high set on October 6. The sell-off reflects growing fears that Democratic control of both chambers of Congress, along with wins in key governors' races, could trigger stricter regulation of AI infrastructure buildouts across the United States. Jordan Watson, portfolio manager at Tandem Investment Advisors, cautioned that the broader market rally and rotation out of AI stocks may prove temporary, warning of continued volatility as investors digest potential policy implications.