NEW YORK - (AP) - Stocks plunged again Wednesday as investorsturned their attention back to the weak economy and Europe's debtproblems. Most of the big gains that followed a Federal Reservepledge to extend super-low interest rates vanished.The Dow Jones industrial average fell 520 points, or 4.6percent, to 10,719. The S&P 500 fell 52, or 4.4 percent, to 1,120,and the Nasdaq fell 101 points, or 4.1 percent, to 2,381.

On Tuesday, the Dow gained 429 points after the Fed said itplanned to keep interest rates extremely low at least through themiddle of 2013.