The Standard & Poor’s GSCI Spot Index of 24 raw materials fell 1 percent to settle at 665.30 at 4 p.m. New York time, led by grains.
The UBS Bloomberg CMCI gauge of 26 prices dropped 1.2 percent to 1,610.05.
Wheat fell the most in three weeks as an unexpected drop in U.S. exports dimmed prospects for demand.
Export sales were 279,877 metric tons in the week that ended on Oct. 4, down 8.8 percent from a week earlier, the U.S. Department of Agriculture said. That trailed 400,000 to 625,000 tons forecast by analysts in a Bloomberg survey. Accumulated exports since June 1 have dropped 9 percent from a year earlier.
Wheat futures for December delivery fell 3.3 percent to $8.5675 a bushel on the Chicago Board of Trade, the biggest decline for a most-active contract since Sept. 17.
Corn futures for December delivery dropped 2.7 percent to $7.5275 a bushel, the biggest decline since Sept. 17.
Soybean futures for November delivery fell 1.7 percent to $15.225 a bushel.
Copper fell, capping the biggest weekly drop in three months, as signs of slowing scrap-metal purchases and bank lending in China fueled concern that demand will weaken as the global economy sputters.
On the Comex in New York, copper futures for December delivery slid 1.3 percent to $3.703 a pound. The price fell 2 percent this week, the most since July 6.
On the London Metal Exchange, copper for delivery in three months fell 1.3 percent to $8,130 a ton ($3.69 a pound). Zinc, nickel, aluminum lead and tin also dropped.
Gasoline fell, capping a second weekly loss, on speculation that supplies will increase as U.S. refineries complete repairs.
On the New York Mercantile Exchange, gasoline futures for November delivery tumbled 2.1 percent to $2.8928 a gallon, the lowest settlement since Oct. 3. The price declined 2 percent this week.
Heating-oil futures for November dropped declined 1 percent to $3.2239 a gallon.
Crude oil fell after the International Energy Agency reduced its forecast for global demand, saying slower economic growth may limit fuel consumption.
On the Nymex, oil futures for November delivery dropped 0.2 percent to $91.86 a barrel.
Brent futures for November settlement fell 0.9 percent to $114.62 a barrel on the London-based ICE Futures Europe exchange.
BP Plc bought two more North Sea Forties cargoes today, bringing its purchases of October loading shipments to six. No bids or offers were made for Russian Urals blend in Europe.
Gold declined, capping the biggest weekly drop in three months, amid concern that demand has declined in China, the world’s largest second-biggest buyer.
On the Comex, gold futures for December delivery fell 0.6 percent to $1,759.70 an ounce. The price dropped 1.2 percent, the most since July 6.
Silver futures for December delivery fell 1.2 percent to $33.669 an ounce. The 2.6 percent decline this week was the biggest since June 22.
On the Nymex, platinum futures for January delivery slumped 1.8 percent to $1,659.30 an ounce, capping a 2.8 percent drop this the week. Palladium futures for December delivery slipped 1.8 percent to $639.05 an ounce, the biggest drop since Sept. 26.
Sugar fell, capping the longest slump in five weeks, on speculation that demand is waning as production outpaces consumption.
Raw sugar for March delivery fell 2 percent to 20.05 cents a pound on ICE Futures U.S. in New York. The price dropped for the third straight day, the longest slump since Sept. 6. The commodity has tumbled 23 percent in the past year.
Arabica-coffee futures for December delivery rose 0.6 percent to $1.617 a pound on ICE.
Cocoa futures for December delivery declined gained 0.6 percent to $2,366 a ton.
Cotton futures for December delivery rose 0.9 percent to 71.36 cents a pound, the biggest advance since Sept. 18.
Orange-juice futures for November delivery fell 0.9 percent to $1.126 a pound. This week, the commodity dropped 2.2 percent.
Natural gas rose, capping the third straight weekly gain, on speculation that U.S. stockpiles will fall short of capacity before lower temperatures boost demand for heating.
On the Nymex, gas futures for November delivery rose 0.2 percent to $3.611 per million British thermal units. The price gained 6.3 percent this week.
U.K. for Oct. 15 advanced as Norwegian imports dropped. The price climbed 0.2 percent to 64.05 pence a therm at 4:34 p.m. London time, according to broker data on Bloomberg.
Month-ahead gas fell 0.3 percent to 63.35 pence a therm. That’s equivalent to $10.18 per million Btu.
Hog futures rose for the third day this week on signs of increasing U.S. demand for pork.
On the Chicago Mercantile Exchange, hog futures for December settlement rose 1.1 percent to 78.375 cents a pound. The price advanced 2.4 percent this week, the second straight gain.
Cattle futures for December delivery fell 0.3 percent to settle at $1.255 a pound.
Feeder-cattle futures for November settlement advanced 0.3 percent to $1.44225 a pound.
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