Mizuho Financial Group, Inc
”Three Japanese big banks, namely the Bank of Tokyo-Mitsubishi UFJ, Sumitomo Mitsui Bank and Mizuho Bank, have started interactions in the form of telegraphic transfer—an electronic method of transferring funds—and L/C at sight with a number of Iranian banks." (May 2017)
Lists a representative office in Tehran, Iran on its company website.
"Reports issued by U.S. researchers attempting to document activity by multinational companies in Iran have named...units of Japan's three largest banks--Mitsubishi UFJ Financial Group Inc, Sumitomo Mitsui Financial Group and Mizuho Financial Group Inc--as doing business that could possibly run afoul of new U.S. rules. A widely circulated report issued this year by a former U.S. Treasury Department official on global banks doing business with Iranian banks named the Big Three Japanese financial institutions. Spokespeople for the three Japanese banks declined to comment on the accuracy of the report, or how the law might affect their operations in Iran." (Wall Street Journal, "New U.S. Law on Iran May Hurt Japanese Firms," 7/1/2010).