What Is a Keiretsu? a Keiretsu Is a Group of Companies That Are Linked Together by Cross-Shareholdings and Other Business Relationships. These Companies Often Cooperate with Each Other in Various Ways, Such as by Sharing Technology, Providing Each Other with Financial Support, and Collaborating on Joint Ventures. Keiretsus Are a Common Feature of the Japanese Economy, and They Play a Significant Role in the Country's Economic Development.