It is thought that the deal will be used by Mizuho Corporate Bank, which is the institutional banking wing of the Japanese bank, to facilitate acquiring pesos at cheaper rates to fund its ventures in Mexican energy projects and to provide a bedrock for expansion in the territory.
Currently, there are 300 Japanese-owned companies in Mexico, which Mizuho intends to help with the transfer of investment money to the United States and Japan.
On Banorte's part, the union marks the end of a period when it had been seeking to end its status as the only large bank in the country that is not afforded the financial muscle and protection of coming under the ownership umbrella of an overseas banking giant.
Last week Mizuho announced it would accept Citigroup's offer of $14.51 per share for its 4.8 per cent stake in scandal-hit Japanese brokerage Nikko Cordial.
Analysts perceive that Mizuho hopes co-operation with the US banking giant will help in its plans to enter the US securities market.