This merger was the first case to be subject to the Special Measures Act on Antimonopoly, which allows for an oligopoly on an exceptional basis.

The forerunner of the Aomori Bank was The 59th National Bank (第五十九国立銀行, dai-gojūku kokuritsu ginkō), was established January 20, 1879, in Hirosaki by the former karō of Hirosaki Domain and many former samurai, as a vehicle to invest the stipends issued by the new Meiji government in compensation for their loss in samurai status.

In Japan, Michinoku had offices in Hokkaidō, Akita, Iwate, Miyagi, and Saitama Prefectures, as well as a branch in Tokyo.

These mascots were used until 2004, when the bank decided to stop using the characters in order to rehabilitate its image as the “Tom and Jerry Bank.” In 1995, Michinoku opened a representative office in Yuzhno-Sakhalin, and four years later established a subsidiary in Moscow.

Outside Japan, Michinoku has established Michinoku Finance (Hong Kong) Ltd in Hong Kong, established representative offices in Wuhan and Shanghai, China, and has opened three branches throughout Russia in Moscow, Khabarovsk, and Yuzhno-Sakhalinsk, through a subsidiary corporation, The Michonoku Bank (Moscow), though expansion into Russia has met with some controversy.

Michinoku Bank was the bank that was used in the “Anita Scandal.” This scandal involved a Japanese businessman for the Aomori Prefectural Public Housing Corporation who was arrested for funneling funds in excess of 13 million US dollars to his Chilean wife, Anita Alvadoro.

This prompted a response from the Japanese Financial Services Agency that Michinoku reform its business practices.

Daidōji was said to have developed an interest in Russia after hearing from his father, who had studied in Europe, say that Russians were different from other Europeans in that they did not discriminate against Japanese.

Industry experts and former employees have criticized this move, claiming that “while the reason for the expansion was that the market in the prefecture was saturated, it was a really risky move,” and “the expansion of business into Russia has come at the expense of the development of the firm.” While the Russian subsidiary claimed a 240 million yen in pretax profits in December 2004, Michinoku injected 2.1 billion yen of capital into the subsidiary in August of that year.