The Dow Jones industrial average plunged 353 points, or 2.3 per cent, to 14,758 points Thursday.
The Dow has lost 560 points in the past two days, wiping out its gains from May and June.
The Standard & Poor's 500 dropped 40 points, or 2.5 per cent, to 1,588. The Nasdaq fell 78 points, or 2.3 per cent, to 3,364 points.
The price of gold dropped and bond yields rose sharply.
Stocks fell across the board. Twenty stocks fell for every one that rose on the New York Stock Exchange. Trading was very heavy at 4.8 billion shares.