The Standard & Poor’s GSCI Spot Index of 24 raw materials rose 1.2 percent to settle at 675.03 at 4 p.m. in New York, led by precious metals.
The UBS Bloomberg CMCI Index of 26 prices advanced 0.7 percent to 1,601.7.
Gold rose, posting the biggest monthly gain since January, as Federal Reserve Chairman Ben S. Bernanke said more bond purchases are an option to aid the U.S. economy, lifting demand for the metal as an inflation hedge.
At an annual forum in Jackson Hole, Wyoming, Bernanke said the central bank “will provide additional policy accommodation as needed” to promote growth. Bernanke used the speech in 2010 to signal an additional $600 billion of debt buying in a second round of quantitative easing, known as QE.
On the Comex in New York, gold futures for December delivery jumped 1.8 percent to $1,687.60 an ounce at 1:45 p.m. on the Comex in New York, capping a 4.6 percent rise in August.
Silver futures for December delivery climbed 3.3 percent to $31.442 an ounce.
On the New York Mercantile Exchange, platinum futures for October delivery rose 2.2 percent to $1,537.30 an ounce.
Copper rose, snapping the longest slump in 12 weeks, after Bernanke said the central bank may need to provide more stimulus to revive sluggish job growth.
On the Comex, copper futures for December delivery climbed 0.3 percent to $3.457 a pound. The price dropped in the previous five sessions, the longest slide since early June.
On the London Metal Exchange, copper for delivery in three month climbed 0.6 percent to $7,615 a metric ton ($3.46 a pound).
Crude oil rose, capping the biggest monthly gain since October, as Bernanke said he wouldn’t rule out more stimulus to boost the economy.
On the Nymex, oil futures for October delivery rose 2 percent to $96.47 a barrel. The price gained 9.6 percent this month.
Brent oil for October settlement climbed 1.7 percent to $114.57 a barrel on the London-based ICE Futures Europe exchange.
BP Plc sold two lots of North Sea Forties crude at a higher price than yesterday’s trade. No bids or offers were made for Russian Urals in Europe.
Total SA Chief Executive Officer Christophe de Margerie
Gasoline advanced after Bernanke indicated the central bank may add economic stimulus and on speculation that Hurricane Isaac caused inventories to tighten.
On the Nymex, gasoline futures for September delivery rose 0.8 percent to $3.1056 a gallon.
Natural gas posted the first weekly gain since July on forecasts of above-normal temperatures that may spark more demand for the power-plant fuel.
On the Nymex, gas futures for October delivery rose 1.9 percent to $2.799 per million British thermal units, capping a 3.6 percent advance for the week.
U.K. gas for within-day delivery rose for the second straight day as imports from Norway declined.
Gas climbed 1.05 pence to 57.4 pence a therm at 4:57 p.m. London time. The October price rose 1.1 percent to 58.91 pence a
Cocoa futures rose, capping the longest rally in 19 months, on concern that supplies will be limited from West Africa, the world’s top producing region.
On ICE Futures U.S. in New York, cocoa for December delivery advanced 0.3 percent to $2,610 a metric ton, the seventh straight gain and the longest rally since January 2011.
Raw-sugar futures for October delivery advanced 0.2 percent to 19.78 cents a pound.
Cotton futures for December delivery rose 0.4 percent to 77.26 cents a pound.
Arabica-coffee futures for December delivery added 0.8 percent to $1.6475 a pound.
Cattle futures rose, capping the longest run of monthly gains in almost two years, on the outlook for shrinking supplies of beef amid the most-severe U.S. Midwest drought since 1936.
On the Chicago Mercantile Exchange, cattle futures for October delivery rose 0.4 percent to $1.26025 a pound. Prices climbed for the fourth straight month, the longest rally since September 2010.
Feeder-cattle futures for October settlement climbed 1.2 percent to $1.46675 a pound.
Soybeans and corn fell on speculation that demand will slow after a crop-damaging U.S. drought boosted prices to records this month.
On the Chicago Board of Trade, soybean futures for November delivery dropped 0.4 percent to $17.565 a bushel. The oilseed gained 7 percent in August after yesterday touching a record $17.7125.
Corn futures for December delivery retreated 1.1 percent to $7.9975 a bushel.