Shares of General Motors and Stellantis fell Tuesday after President-elect Donald Trump threatened to impose a 25% tariff on goods imported from Canada and Mexico. The proposed tariffs would significantly affect the automotive industry, which relies on lower-cost production in Mexico. UBS reports that the automotive sector accounts for 26% of U.S. imports from Mexico and 12% from Canada. GM and Stellantis saw significant drops in their stock prices, while other automakers like Ford and Toyota also experienced declines.