Prices for platinum and palladium are edging higher, pushed up by supply worries.

Both metals have been rising for most of the year. That's partly because traders believe the economy and auto industry are improving. Palladium and platinum are used in manufacturing, including for catalytic converters in cars and trucks.

Prices have also been up because of concerns about supply. Dave Meger, director of metals trading at Vision Financial Markets in Chicago, says Russia's stockpiles are expected to fall this year. Strikes at mines in South Africa have also disrupted supply, and Zimbabwe is curbing the amount of land available for mining.

Gold and silver slipped. Benchmark crude fell after the government reported higher U.S. stockpiles.

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