Wall Street extends declines
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 fell 136.99 points, or 1.59 percent, to 8,492.69. The Standard & Poor's 500 Index was down 19.53 points, or 2.22 percent, at 860.20. The Nasdaq Composite Index lost 46.80 points, or 3.04 percent, to 1,493.92.
(Reporting by Leah Schnurr; Editing by Jan Paschal)