[An updated version of this article can be found at Money Supply in the 2nd edition.]
What Is the Money Supply?
The U.S. money supply comprises currency—dollar bills and coins issued by the Federal Reserve System and the Treasury—and various kinds of deposits held by the public at commercial banks and other depository institutions such as savings and loans and credit unions. On June 30, 1990, the money supply, measured as the sum of currency and checking account deposits, totaled $809 billion. Including some types of savings deposits, the money supply totaled $3,272 billion. An even broader measure totaled $4,066 billion.
These measures correspond to three definitions of money that the Federal Reserve uses: M1, a narrow measure of money's function as a medium of exchange; M2, a broader measure that also reflects money's function as a store of value; and M3, a still broader measure that covers items that many regard as close substitutes for money.
The definition of money has varied. For centuries physical commodities, most commonly silver or gold, served as money. Later, when paper money and checkable deposits were introduced, they were convertible into commodity money. The abandonment of convertibility of money into a commodity since August 15, 1971, when President Nixon discontinued converting U.S. dollars into gold at $35 per ounce, has made the U.S. and other countries' monies into fiat money—money that national monetary authorities have the power to issue without legal constraints.
Why Is the Money Supply Important?
Because money is used in virtually all economic transactions, it has a powerful effect on economic activity. An increase in the supply of money puts more money in the hands of consumers, making them feel wealthier, thus stimulating increased 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 loans.
Opposite effects occur when the supply of money falls, or when its rate of growth declines. Economic activity declines and either disinflation (reduced inflation) or deflation (falling prices) results.
What Determines 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.
Here's how it works. The Federal Reserve requires commercial banks and other financial institutions to hold as reserves a fraction of the deposits they accept. Banks hold these reserves either as cash in their vaults or as deposits at Federal Reserve banks. In turn, the Federal Reserve controls reserves by lending money to banks and changing the "Federal Reserve discount rate" on these loans and by "open-market operations." The Federal Reserve uses open-market operations to either increase or decrease reserves. To increase reserves, the Federal Reserve buys U.S. Treasury securities by writing a check drawn on itself. The seller of the Treasury security deposits the check in a bank, increasing the seller's deposit. The bank, in turn, deposits the Federal Reserve check at its district Federal Reserve bank, thus increasing its reserves. The opposite sequence occurs when the Federal Reserve sells Treasury securities: the purchaser's deposits fall and, in turn, the bank's reserves fall.
If the Federal Reserve increases reserves, a single bank can make loans up to the amount of its excess reserves, creating an equal amount of deposits. The banking system, however, can create a multiple expansion of deposits. As each bank lends and creates a deposit, it loses reserves to other banks, which use them to increase their loans and, thus, create new deposits, until all excess reserves are used up.
If the required reserve ratio is 20 percent, then starting with new reserves of, say, $1,000, the most a bank can lend is $800, since it must keep $200 as reserves against the deposit it simultaneously sets up. When the borrower writes a check against this amount in his bank A, the payee deposits it in his bank B. Each new demand deposit that a bank receives creates an equal amount of new reserves. Bank B will now have additional reserves of $800 of which it must keep $160 in reserves, so it can lend out only $640. The total of new loans granted by the banking system as a whole in this example will be five times the initial amount of excess reserve, or $4,000: 800 + 640 + 512.40 + 409.60, and so on.
In a system with fractional reserve requirements, an increase in bank reserves can support a multiple expansion of deposits, and a decrease can result in a multiple contraction of deposits. The value of the multiplier depends on the required reserve ratio on deposits. A high required-reserve ratio lowers the value of the multiplier. A low required-reserve ratio raises the value of the multiplier.
Even if there were no legal reserve requirements for banks, they would still maintain reserves with the Federal Reserve, whose ability to control the volume of deposits would not be impaired. Banks would continue to keep reserves to enable them to clear debits arising from transactions with other banks, to obtain currency to meet depositors' demands, and to avoid a deficit as a result of imbalances in clearings.
The currency component of the money supply is far smaller than the deposit component. The Federal Reserve and the Treasury supply the banks with the currency their customers demand, and when their demand falls, accept a return flow from the banks. The Federal Reserve debits banks' reserves when it provides currency, and credits their reserves when they return currency. In a fractional reserve banking system, drains of currency from banks reduce their reserves, and unless the Federal Reserve provides adequate additional amounts of currency and reserves, a multiple contraction of deposits results, reducing the quantity of money.
Currency and bank reserves added together equal the monetary base, sometimes known as high-powered money. The Federal Reserve has the power to control the issue of both components. By adjusting the levels of banks' reserve balances, over several quarters it can achieve a desired rate of growth of deposits and of the money supply. When the public and the banks change the ratio of their currency and reserves to deposits, the Federal Reserve can offset the effect on the money supply by changing reserves and/or currency.
The Federal Reserve's techniques for achieving its desired level of reserves—both borrowed reserves that banks obtain at the discount window and nonborrowed reserves that it provides by open-market purchases—have changed significantly over time. At first the Federal Reserve controlled the volume of reserves and of borrowing by member banks mainly by changing the discount rate. It did so on the theory that borrowed reserves made member banks reluctant to extend loans, because their desire to repay their own indebtedness to the Federal Reserve as soon as possible was supposed to inhibit their willingness to accommodate borrowers. In the twenties, when the Federal Reserve discovered that open-market operations also created reserves, changing nonborrowed reserves offered a more effective way to offset undesired changes in borrowing by member banks. In the fifties, the Federal Reserve sought to control what are called free reserves, or excess reserves minus member bank borrowing.
In recent decades the Federal Reserve has specified a narrow range for the federal funds rate, the interest rate on overnight loans from one bank to another, as the objective of open-market operations. It has interpreted a rise in interest rates as tighter monetary policy and a fall as easier monetary policy. But interest rates are an imperfect indicator of monetary policy. If easy monetary policy is expected to cause inflation, lenders demand a higher interest rate to compensate for this inflation, and borrowers are willing to pay a higher rate because inflation reduces the value of the dollars they repay. Thus, an increase in expected inflation increases interest rates. Between 1977 and 1979, for example, U.S. monetary policy was easy and interest rates rose. Similarly, if tight monetary policy is expected to reduce inflation, interest rates could fall.
From 1979 to 1982, the Federal Reserve tried to control nonborrowed reserves to achieve its monetary target. The procedure produced large swings in both money growth and interest rates. Forcing nonborrowed reserves to decline when above target led borrowed reserves to rise because the Federal Reserve allowed banks access to the discount window when they sought this alternative source of reserves. Since 1982 the Federal Reserve has targeted the borrowed reserves level but downgraded the importance of achieving monetary targets. In early 1991 it appeared to be paying attention once again to monetary growth rates.
If the Federal Reserve determines the magnitude of the money supply, what makes the nominal value of money in existence equal to the amount that people want to hold? One way to make that correspondence happen is for interest rates to change. A fall in interest rates increases the amount of money that people wish to hold; a rise in interest rates decreases the amount they want. Another way to make the money supply equal the amount demanded is for prices to change. When people hold more nominal dollars than they want, they spend them faster, causing prices to rise. These rising prices reduce the purchasing power of money until the amount people want equals the amount available. Conversely, when people hold less money than they want, they spend more slowly, causing prices to fall. As a result, the real value of money in existence just equals the amount people are willing to hold.
An Alternative View of Money Supply Determination
A different view is that the magnitude of the money supply is determined not by the Federal Reserve but by the decisions of the public and the banks. In this view banks supply only as much in deposits as the public wants to hold. Additional reserves cannot lead to an increase in the supply of deposits if the public does not want them. People will simply repay loans and shrink the money supply. According to this view a decline in the money supply is a response to a decline in people's demand to hold it, not an independent action by suppliers to reduce the quantity of money.
This alternative view, however, fails to account for the close relationship between bank reserves and deposits. If the alternative view were correct, we would observe discrepancies between movements of reserves and deposits over quarterly periods. We do not. Deposits cannot grow faster than reserves, given the required reserve ratio, no matter how avid the public's demand. Deposits may grow slower than reserves, but only if banks, fearing for their own safety in the absence of a reliable lender of last resort, want to accumulate excess reserves, as happened in the thirties. To hold excess reserves means they forgo the opportunity to hold earning assets. That is why banks usually hold minimal excess reserves.
History of the U.S. Money Supply
From the founding of the Federal Reserve in 1913 until the end of World War II, the money supply tended to grow at a higher rate than the growth of nominal GNP. This increase in the ratio of money supply to GNP shows an increase in the amount of money as a fraction of their income that people wanted to hold. From 1946 to 1980, nominal GNP tended to grow at a higher rate than the growth of the money supply, an indication that the public reduced its money balances relative to income. Until 1986, money balances grew relative to income; since then they have declined relative to income. Economists explain these movements by changes in price expectations, as well as changes in interest rates that make money holding more or less expensive. If prices are expected to fall, the inducement to hold money balances rises since money will buy more if the expectations are realized; similarly, if interest rates fall, the cost of holding money balances rather than spending or investing them declines. If prices are expected to rise or interest rates rise, holding money rather than spending or investing it becomes more costly.
The money supply has tended to rise more rapidly during business cycle expansions than during business cycle contractions. The rate of rise has tended to slow down before the peak in business and to accelerate before the trough.
Since 1914 an actual decline of the money supply has occurred during only three business cycle contractions, each of which was severe as judged by the decline in output and rise in unemployment: 1920 to 1921, 1929 to 1933, 1937 to 1938. The severity of the economic decline in each of these cyclical downturns, it is widely accepted, was a consequence of the reduction in the quantity of money, particularly so for the downturn that began in 1929, when the quantity of money fell by one-third, an unprecedented reduction.
The United States has experienced three major price inflations since 1914, and each has been preceded and accompanied by a corresponding increase in the rate of growth of the money supply: 1914 to 1920, 1939 to 1948, 1967 to 1980. An acceleration of money growth in excess of real output growth has invariably produced inflation—in these episodes and in many earlier examples in this country and elsewhere in the world.
To ignore the magnitude of money supply changes is to court monetary disorder. That is the lesson that the history of money supply teaches.
Anna J. Schwartz is an economist at the National Bureau of Economic Research in New York. She is a past president of the Western Economic Association.
Eatwell, John, Murray Milgate, and Peter Newman, eds. The New Palgrave Money. 1989.
Friedman, Milton, and Anna J. Schwartz. A Monetary History of the United States, 1867-1960. 1963.
McCallum, Bennett T. Monetary Economics. 1989.
Rasche, Robert H., and James M. Johannes. Controlling the Growth of Monetary Aggregates. Rochester Studies in Economics and Policy Issues. 1987.
Schwartz, Anna J. Money in Historical Perspective. 1987.
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