Technology and industrial stocks, which would stand to suffer greatly in a protracted trade war, led the way lower. The U.S. was set to impose higher tariffs on China on Friday, a day after representatives from both nations are scheduled to resume trade talks in Washington.
The S&P 500 index slumped 48.42 points, or 1.7%, to 2,884.05.
The Dow Jones Industrial Average lost 473.39 points, or 1.8%, to 25,965.09.
The Nasdaq composite fell 159.53 points, or 2%, to 7,963.76.
The Russell 2000 index of small company stocks gave up 32.66 points, or 2%, to $1,582.31.
For the week:
The S&P 500 is down 61.59 points, or 2.1%.
The Dow is down 539.86 points, or 2%.
The Nasdaq is down 200.24 points, or 2.5%.
The Russell 2000 is down 31.71 points, or 2%.
For the year:
The S&P 500 is up 377.20 points, or 15%.
The Dow is up 2,637.63 points, or 11.3%.
The Nasdaq is up 1,328.48 points, or 20%.
The Russell 2000 is up 233.75 points, or 17.3%.