Updated at 4:15 p.m. ET
The Dow Jones industrial average lost 459 points Monday, falling 1.9 percent, as tech stocks led the markets down and investors eyed growing trade tensions with China. Earlier in the day, the Dow was down more than 700 points.
Amazon tumbled more than 5 percent after President Trump criticized the company in tweets. The tech-heavy Nasdaq index lost 2.7 percent. The S&P 500 index lost 59 points, or 2.2 percent.
Investors are also worried about a growing trade war with China. On Monday, Beijing retaliated against U.S. tariffs on steel and aluminum imports by unveiling a list of 128 imports from the U.S., including agriculture products ranging from fruit to frozen pork, that would be subject to higher import duties.
NPR's Yuki Noguchi reported:
"Investors are bailing out of tech stocks, amid concerns that regulators will clamp down on some major companies. Facebook faces backlash from users and lawmakers, for the unauthorized sharing of millions of its users' personal information. Tesla faces scrutiny for its semi-automated driving technology, which ... may have led to a fatal crash. Then over the weekend President Trump signaled his intention of cracking down on Amazon for what he calls unfair business practices."
"This is definitely a flight to safety type of market," Peter Jankovskis of Oakbrook Investments told Bloomberg News. "You're seeing people coming out of the stocks that had been performing well."