BMW, Daimler to expand purchasing tie-up

German carmakers BMW and Daimler will expand their cooperation in purchasing automotive components, a BMW board member told German magazine WirtschaftsWoche on Saturday.

Up to 10 percent of a car's components can be purchased jointly by the two companies without damaging their brand names, Herbert Diess said.

Mechanical systems, wheels and tyres are some of the items the two are buying jointly, he added.

Diess said BMW is expected to achieve its goal to save 4 billion euros ($5.68 billion) in purchasing expenditures by 2012 and might even exceed this amount.