Seafirst Corporation was a bank holding company based in Seattle, Washington. Formed on November 11, 1929, from the merger of Seattle's three largest banks, the First National Bank Group, the Dexter Horton National Bank (founded 1870 by Dexter Horton), and Seattle National Bank, the bank was originally named First Seattle Dexter Horton National Bank. In 1931, the bank changed its name to First National Bank of Seattle, and again in 1935 to Seattle-First National Bank. In 1944, the bank won a case before the US Supreme Court, United States v. Seattle-First Nat. Bank, by arguing that it did not have to pay a transfer tax when it converted from a state to a federally chartered bank. In 1970 it was using the name Firstbank; in 1974 the name Seafirst was adopted instead.