who controls the amount of money in circulation
Money creation Monetary policy regulates a country's money supply, the amount of broad currency in circulation. Almost all modern nations have central banks such as the United States Federal Reserve System, the European Central Bank (ECB), and the People's Bank of China for conducting monetary policy. Charged with the smooth functioning of the money supply and financial markets, these institutions are generally independent of the government executive.
Currency A currency (from Middle English: curraunt, "in circulation", from Latin: currens, -entis), in the most specific use of the word, refers to money in any form when in actual use or circulation as a medium of exchange, especially circulating banknotes and coins.[1][2] A more general definition is that a currency is a system of money (monetary units) in common use, especially in a nation.[3] Under this definition, US dollars, British pounds, Australian dollars, European euros and Russian ruble are examples of currency. These various currencies are recognized stores of value and are traded between nations in foreign exchange markets, which determine the relative values of the different currencies.[4] Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance.