It was a rare major Japanese commercial bank unaffiliated with either a keiretsu group or a sogo shosha trading company.

It established several overseas offices in the 1950s and 1960s to support its municipal finance operations.

[1] Dai Nippon Mujin was a mutual savings and loan company established in 1940.

The bank grew consistently through the 1970s and 1980s and opened numerous overseas offices.

The merger was aimed at leveraging these synergies, as well as providing stronger competition against European banks, which were expected to consolidate following a deregulation in 1992.