A central bank, reserve bank, or monetary authority is a public institution that usually issues the currency, regulates the money supply, and controls the interest rates in a country. Central banks often also oversee the commercial banking system of their respective countries. In contrast to a commercial bank, a central bank possesses a monopoly on printing the national currency, which usually serves as the nation's legal tender. Examples include the European Central Bank (ECB), the Federal Reserve of the United States, and the People's Bank of China. - Source: Wikipedia