Banks often lend each other money over night to meet their reserve requirements. The rate on such loans, known as the "federal funds rate," is a key gauge of how "tight" or "loose" monetary policy is at a given moment. The Fed's third tool is the discount rate, or the interest rate that commercial banks pay to borrow funds from Reserve Banks. By raising or lowering the discount rate, the Fed can promote or discourage borrowing and thus alter the amount of revenue available to banks for making loans. These tools allow the Federal Reserve to expand or contract the amount of money and credit in the U.S. economy. If the money supply rises, credit is said to be loose. In this situation, interest rates tend to drop, business spending and consumer spending tend to rise, and employment increases; if the economy already is operating near its full capacity, too much money can lead to inflation, or a decline in the value of the dollar. When the money supply contracts, on the other hand, credit is tight. In this situation, interest rates tend to rise, spending levels off or declines, and inflation abates; if the economy is operating below its capacity, tight money can lead to rising unemployment. Many factors complicate the ability of the Federal Reserve to use monetary policy to promote specific goals, however. For one thing, money takes many different forms, and it often is unclear which one to target. In its most basic form, money consists of coins and paper currency. Coins come in various denominations based on the value of a dollar: the penny, which is worth one cent or one-hundredth of a dollar; the nickel, five cents; the dime, 10 cents; the quarter, 25 cents; the half dollar, 50 cents; and the dollar coin. Paper money comes in denominations of $1, $2, $5, $10, $20, $50, and $100. A more important component of the money supply consists of checking deposits, or bookkeeping entries held in banks and other financial institutions. 94