Stocks tumbled in heavy volume on Monday, with more than 1,000 stocks traded on the New York Stock Exchange hitting 52-week lows, after rating agency Standard & Poor's cut the United States' perfect AAA credit rating, rattling already jittery investors.

About 7 billion shares traded on the New York Stock Exchange, NYSE Amex and Nasdaq by noon New York time (1600 GMT), making it the second-busiest morning of the year so far.

Declining stocks outnumbered advancing ones on the NYSE by a ratio of 30 to 1, while on the Nasdaq, slightly fewer than nine stocks fell every one that rose.

Among the companies hitting 52-week lows were JPMorgan Chase & Co, down 5.6 percent at $35.48, after hitting a low of $35.30. Goldman Sachs fell 5.3 percent to $118.52, after hitting a low of $118.43.

Bank of America tumbled 14.3 percent to $7 after hitting a 52-week low of $6.83 earlier, and Cisco Systems fell 3.8 percent to $14.36 after falling to as low as $14.23.

The Dow Jones industrial average dropped 357.27 points, or 3.12 percent, to 11,087.34. The Standard & Poor's 500 Index fell 45.23 points, or 3.77 percent, to 1,154.15. The Nasdaq Composite Index lost 98.24 points, or 3.88 percent, to 2,434.17.

(Reporting by Rodrigo Campos; Editing by Jan Paschal)