In July, BMW announced a new partnership with Fiat for the use of U.S. Mini dealerships by Alfa Romeo, and in August the carmaker turned to negotiations with Mercedes-Benz over procurement and purchasing agreements. Now those agreements have come to fruition and joint-purchasing arrangments are already underway according to the latest reports.

Klaus Draeger, development head for BMW, revealed in an interview with Germany's Auto Motor & Sport that joint purchases for basic components such as heat exchangers, xenon ballasts and air conditioning systems were already occurring. Both German luxury marques are looking to reduce costs by combining their purchases for vehicle components that aren’t visible to consumers.

Earlier reports indicated that BMW and Mercedes could share development for their future V12 engines - a project that could possibly even include Aston Martin. Aston Martin and Mercedes are already tied in negotiations for a deal to share everything from platforms to engines and transmissions. Draeger reaffirmed this aspect of the cooperation as well, saying that BMW is ready to consider selling its engines to competitors, especially Mercedes. Talks are ongoing with Aston Martin, but nothing has come of that as yet.

In 2007, the idea of cooperation between BMW and Mercedes was somewhat controversial, even to the companies' own spokespersons. At one point, Mercedes even alleged that it had no interest in working with BMW. But times, and economic circumstances have changed. Leveraging the massed buying power of the two companies can help cut costs without affecting product quality in any way.

"The use of economies of scale is successively being implemented. We do not need to wait for a model change or official announcements," said Draeger.

Official commentary on the agreement is still forthcoming, but Draeger's statements leave the matter with no doubt: an agreement is in place and already functioning.