There are several definitions of the supply of money.M1 is narrowest and most commonly used. It includes all currency (notes and coins) in circulation, all checkable deposits held at banks (bank money), and all traveler's checks. A somewhat broader measure of the supply of money is M2, which includes all of M1 plus savings and time deposits held at banks. An even broader measure of the money supply is M3, which includes all of M2 plus large denomination, long-term time deposits—for example, certificates of deposit (CDs) in amounts over $100,000. Most discussions of the money supply, however, are in terms of the M1 definition of the money supply. Federal Reserve policy is the most important determinant of the money supply. The Federal Reserve affects the money supply by affecting its most important component, bank deposits. The Fed creates the money while the U.S. Treasury prints it.
Because money is used in virtually all economic transactions, it has a powerful effect on economic activity. An increase in the supply of money works both through lowering interest rates, which spurs investment, and through putting more money in the hands of consumers, making them feel wealthier, and thus stimulating spending. Business firms respond to increased sales by ordering more raw materials and increasing production. The spread of business activity increases the demand for labor and raises the demand for capital goods. In a buoyant economy, stock market prices rise and firms issue equity and debt. If the money supply continues to expand, prices begin to rise, especially if output growth reaches capacity limits. As the public begins to expect inflation, lenders insist on higher interest rates to offset an expected decline in purchasing power over the life of their