The fears had shadowed Wall Street off and on for months. Then, all at once, everyone rushed for the exits.
The stock-market rout on Thursday, which began soon after the opening bell on the New York Stock Exchange, worsened as the day wore on, pulling down everything from high-flying chipmakers like Nvidia Corp. to defensive fallbacks like Walmart Inc.
But hardest hit were the companies at the heart of the artificial-intelligence boom that earlier this year sent the stock market to one record high after another — and sowed worries that it was a bubble bound to burst.
All it took to send them tumbling on Thursday was the prospect that Democrats’ sweeping victory in the Congressional elections may herald a political shift that will tap the brakes on the industry’s breakneck growth and the hundreds of billions of dollars being plowed into the computer equipment that powers it.
By the time the session came to a close, the Nasdaq 100 Index was down over 6%, its worst drop since the height of the tailspin unleashed by Covid-19 in March 2020.