Stocks slumped for a second day as concern about the looming package of tax rises and spending cuts offset reports showing a fall in the number of claims for unemployment benefits and rising U.S. exports.
Investors are concerned that politicians in Washington may not be able to hammer out an agreement on how to reduce the U.S. budget deficit before a Jan. 1 deadline.
The Dow Jones industrial average fell 121.41 points, or 0.9 percent, to 12,811.32.
The Standard & Poor's 500 index fell 17.02 points, or 1.2 percent, to 1,377.51
The Nasdaq composite fell 41.71 points, or 1.4 percent, to 2,895.58.
For the week:
The Dow is down 281.84 points, or 2.2 percent.
The S&P 500 is down 36.69 points, or 2.6 percent.
The Nasdaq is down 86.55 points, or 2.9 percent.
For the year:
The Dow is up 593.76 points, or 4.9 percent.
The S&P is up 119.91 points, or 9.5 percent.
The Nasdaq is up 290.43, or 11.2 percent.