The Mitsui Group keiretsu of course had its origins in the Mitsui zaibatsu, but this archetypical political-financial firm did not pass through the transition of Japanese defeat in World War II with its power and prestige intact. There was considerable loss of power and influence. In particular the Mitsui Bank which had in effect been the bank of the Imperial government emerged from the transition period as only the eighth largest city bank. In 1990 the Mitsui Bank merged with Taiyo Kobe Bank to raise its stature but the combined banks still did not give Mitsui number one rank. In 1992, perhaps to avoid having the Mitsui name attached to a second place bank, Mitsui changed its bank's name to Sakura.

Sakura Bank is one of the core enterprises of the Mitsui Group but the leadership of the group has been concentrated more in the group's shosha, Mitsui Bussan. The other core enterprise is Mitsui Fudosan, the real estate operation. The chairmanship of the management council for the Mitsui Group is held sequentially by the three core enterprises.