NEW YORK (AP) – Stocks are plummeting at the close after anxiety overtook investors on the first trading day since Standard & Poor’s downgraded American debt.

The Dow Jones industrials closed down 634 points, or 5.5 percent, to 10,809 Monday. It was the first time the Dow fell below 11,000 since November and its biggest one-day point drop since December 2008.

The S&P 500 is closing down 79or 6.7 percent, at 1,119.46. The Nasdaq is down 174.72, or 6.9 percent, at 2,357.69. More than 69 stocks fell for every one that rose on the New York Stock Exchange. Trading volume was heavy at 9.7 billion shares.

Investors are worried about the slowing U.S. economy and escalating debt problems threatening Europe. Money flowed out of stocks and into safer investments, including Treasurys and gold.

(Copyright 2011 The Associated Press. All rights reserved.)