GRIM OUTLOOK: Most commodity prices fell, some to multi-week lows, after a wave of major U.S. corporations offered a grim snapshot of the global economy. Slower growth cuts into demand for many raw materials, from oil and industrial metals to grains and beans.

WINNERS, LOSERS: Prices fell for oil, gold, industrial metals, wheat and corn. Prices rose for natural gas and soybeans.

WHAT'S NEXT: The Federal Reserve will end a two-day meeting on Wednesday. Some commodities investors hope that the central bank will tweak its latest plan to stimulate the economy, but no major announcements are expected.