Monetary authorities are institutions responsible for managing a country's money supply and interest rates. They aim to ensure economic stability by controlling inflation and fostering a healthy financial environment. The most well-known monetary authority is a country's central bank, such as the Federal Reserve in the United States or the European Central Bank in the Eurozone. These authorities use various tools, such as setting interest rates and conducting open market operations, to influence the economy. By adjusting the money supply, they can encourage or discourage borrowing and spending, which ultimately impacts economic growth and employment levels.