News Summary: Wheat tumbles a second day on report

WHEAT TUMBLES: Wheat fell the most in a month, sliding for a second day after the Department of Agriculture raised its estimate for the size of the crop.

WEAKER GRAINS: Corn and Soybean also fell sharply. All three had advanced in the summer as concern that a drought would decimate corn crops and slash harvests. Wheat can be used as a substitute for corn for some uses, such as cattle feed.

OIL EDGES LOWER: Oil fell modestly on concerns about the looming "fiscal cliff." A combination of tax hikes and government spending cuts will take effect Jan. 1 unless President Barack Obama and Congress can reach a compromise to avert it, hobbling the world's largest economy.