The United States Treasury has officially identified Switzerland and Vietnam as currency manipulators.A country's attempt to manipulate the value of its currency involves the central bank buying a lot if its own money.This creates scarcity, which pushes the value of the money up.The U.S. Treasury move may be one of the final strikes against international trading partners by the departing administration of U.S. President Donald Trump.Officials said Switzerland and Vietnam were named because both had intervened in currency markets through June 2020 to prevent effective balance of payments adjustments.A balance of payment is the difference between how much a country pays to other nations and how much it gets paid by other nations.In its currency manipulation report, the Treasury said Vietnam had acted to get "unfair competitive advantage in international trade as well."Foreign currency experts had expected the two countries to be named in the report.