BMW may be considering buying an engineering firm to help it develop a planned environmentally-friendly brand of vehicles.

According to Wirtschaftswoche, a company insider said BMW is not targeting a particular company and is considering all options. The company wants the firm to help it develop an environmentally-friendly low-cost product range quickly.

The development is part of BMW CEO Norbert Reithofer's planned change of strategy outlined at the end of September. The new fourth brand would sit alongside BMW, Mini and Rolls-Royce.

According to the report, BMW had previously considered acquiring a brand, but ruled this out because no existing brands would fit neatly into the group.

Reithofer said in September that acquisitions are on the agenda for BMW, but that no purchase is planned in the next 12 months.