major Japanese banking and financial institution, headquartered in Tokyo, that was formed through the merger of three leading Japanese banks in 2001.

Its origins date to 1880 through the Yokohama Specie Bank, an international bank specializing in foreign exchange. In 1946 Yokohama became the Bank of Tokyo, and its business emphasis was changed to that of an ordinary commercial bank. In 1954 the bank was reorganized as Japan's specialized foreign-exchange bank, and in 1962 it was authorized to issue debentures to support its yen funding. A merger in 1996 between the Bank of Tokyo and the Mitsubishi Bank created the Bank of Tokyo-Mitsubishi, Ltd. Its subsequent merger in 2001 with the Mitsubishi Trust and Banking Corp., Nippon Trust Bank Ltd., and Tokyo Trust Bank Ltd. formed Mitsubishi Tokyo Financial Group Inc., one of Japan's largest banks.