The offices of BMW, Daimler and Volkswagen have been raided as part of a German investigation into steel price fixing.

BMW_Tiexi_Factory

The three German automakers are accused of being part of a six company automotive cartel that engaged in anti-competitive practices to depress the price of steel.

Kay Weidner, a spokesman for Germany's anti-trust office, told Bloomberg that the raids occurred in June and would help investigators establish facts in the case.

BMW, Daimler (parent company of Mercedes-Benz), Volkswagen, parts supplier Bosch, and transmission specialist ZF have all confirmed to the business publication that their offices were raided and that they are cooperating with investigators.

All of the companies declined to give further details. The sixth member of the alleged cartel has not yet outed itself.

It's not known how long the alleged cartel operated for, and whether its anti-competitive behaviour was confined to Germany or the EU.

2016 Audi A4 2.0 TFSI quattro v 2016 BMW 330i v 2016 Mercedes-Benz C250-200

The World Steel Association estimates that the average car uses around 900 kilograms of steel.

If the allegations are proven, the state anti-trust office could impose fines as high as a 10 percent of annual sales, although it's unlikely that it would ask for the maximum fine.