Stocks slumped on Wall Street, led by a sharp slide in technology companies after Apple reported a slowdown in iPhone sales over the holidays in China.
The 5 percent drop in tech stocks Thursday was the biggest for the sector since 2011.
The Apple news jolted markets and reinforced fears that the global economy is slowing. A surprisingly weak report on U.S. manufacturing made matters worse.
Apple dropped 10 percent, erasing $74.6 billion in value. Makers of phone parts also fell.
The Dow Jones Industrial Average fell 660 points, or 2.8 percent, to 22,686.
The broader S&P 500 fell 62 points, or 2.5 percent, to 2,447. The Nasdaq lost 202 points, or 3 percent, to 6,463.
Bond prices rose as investors sought safety, sending yields sharply lower.