Why did the S&P 500 lose over $2 trillion in 40 minutes today?

On Thursday, the S&P 500 fell 2.8%, erasing a 1.6% gain from the previous day and losing roughly $2 trillion in market value in 40 minutes, while broader market losses exceeded $2.3 trillion by midmorning. The selloff followed Democratic wins of both chambers of Congress and important governorships, which investors feared would give the party more influence over how states handle construction of AI data centers. Those concerns weighed on technology and semiconductor shares, and the Nasdaq Composite fell 3.9%, more than 10% below its October record and in correction territory. The Dow Jones Industrial Average dropped 1,153 points, or 2.2%.