Whenever an economy relies on a system of fiat money, as the U:S. economy does” some  must be responsible for regulating the system. In the United States, that agency is the Federal Reserve, often simply called the Fed. If you look at the top of a dollar bill, you will see that it is called a “Federal Reserve Note The Fed is an example of a central bank-an institution designed to over seethe .banking system and regulate the quantity of money’ in the economy. Other major central banks around the world include the Bank of England, the Bank of Japan, and the European Central Sank. ” ‘