Investors flee U.S. stocks as markets react sharply to Trump's tariff plan

Global markets reacted sharply and swiftly after President Donald Trump revealed his much-anticipated tariff plans Wednesday, with investors fleeing U.S. stock indexes and stocks of companies that rely on global supply chains plummeting.

S&P 500 futures, which indicate where it is likely to open Thursday, plunged 3%. Nasdaq 100 futures sold off by more than 4%, and Dow futures slid about 1,000 points, or 2%.

Those indexes just endured their worst quarter in years in large part because of growing concern about the economic impacts of Trump's expected tariff plan.