<P> A keiretsu (系列, literally 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 second half of the 20th century . </P> <P> The members 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 projects . It is a key element of the manufacturing industry in Japan . </P>

The keiretsu tradition in japan serves as a