Keiretsu

A Japanese word referring to the large groups of companies that are a characteristic feature of the Japanese economy, especially in the auto industry. Keiretsu companies do business first and foremost among themselves; tight supplier-buyer relationships within the keiretsu system are a barrier to the penetration of foreign goods in Japan because, everything else being equal, keiretsu members prefer to buy from other keiretsu members; the keiretsu system is a controversial issue in US-Japanese trade relations.
See also horizontal keiretsu, vertical keiretsu