Keiretsu

A keiretsu (系列?, lit. system, series, grouping of enterprises, order of succession) is a set of companies with interlocking business relationships and shareholdings. It is a type of informal business group. The keiretsu maintained dominance over the Japanese economy for the greater half of the 20th century, but are beginning to lose their grip.

The member companies own small portions of the shares in each other's companies, centered on a core bank; this system helps insulate each company from stock market fluctuations and takeover attempts, thus enabling long-term planning in innovative projects. It is a key element of the automotive industry in Japan.