It has previously purchased UnionBanCal and Mitsubishi's head of global banking Tatsuo Tanaka said it is currently examining seven firms of a similar size.
"We want to be one of the top ten banks in the US in terms of assets and profit," Mr Tanaka, who is to become the chairman of UnionBanCal, told Bloomberg.
"I'd like to do a large investment in the US."
Mitsubishi is seeking to increase its overseas profits by more than 40 per cent and above the one trillion yen mark, as domestic loan demand declines.
According to a recent report by the World Bank, Japan's growth rates are forecast to be 2.5 per cent this year and 2.1 per cent in 2011, while its counterparts in east Asia are set to record equivalent growth of 8.7 per cent and 7.8 per cent.
By Asim Shah