Key TakeawaysShares of Nvidia fell more than 8% Monday, slipping into bear market territory.The company's latest quarterly financial results raised questions about what was next for the stock—and the AI trade—and uncertainty driven by US trade policy has further concerned investors.

U.S. stocks face a tenuous moment with the arrival of President Donald Trump's latest tariffs. The benchmark S&P 500 is down about 5% from its February 19 all-time closing high as a series of weakening U.

Investors dumped stocks on Wall Street late Monday after President Donald Trump said his threatened tariffs on Canada and Mexico would go forward as planned early Tuesday.