Wall Street extends declines

NEW YORK (Reuters) - Stocks extended declines on Monday, roiled by worries about how big a bite the global financial crisis has taken out of banks' profits and signs of more economic weakness.

Highlights:

* JPMorgan Chase & Co tumbled after Merrill Lynch cut the stock to an "underperform" rating and forecast a loss for the bank's fourth quarter.

* The Dow Jones industrial average <.DJI> fell 136.99 points, or 1.59 percent, to 8,492.69. The Standard & Poor's 500 Index <.SPX> was down 19.53 points, or 2.22 percent, at 860.20. The Nasdaq Composite Index <.IXIC> lost 46.80 points, or 3.04 percent, to 1,493.92.

(Reporting by Leah Schnurr; Editing by Jan Paschal)