As agreed in the Maastricht Treaty, 11 European Union members began participating in the EMU on January 1, 1999. The 11 countries are Austria, Belgium, Finland, France, Germany, Ireland, Italy, Luxembourg, the Netherlands, Portugal, and Spain. The other four countries — the United Kingdom, Denmark, Sweden, and Greece — either chose not to participate at this time, or did not meet the economic criteria. Under the EMU, the 11 countries have a common central bank (the European Central Bank), and thus a common monetary policy, similar to that of the U.S. Federal Reserve System, and a single currency, called the euro.