Money supply generally is denoted as M1 which is equal to GDP/V, GDP is the gross national product and V is the velocity of money, or on the other hand, generally M3 money supply is equal to M1 times V. The velocity V defines the amount of virtual. Classical dichotomy is the theoretical separation of real and nominal variables. In the classical economic theory, we have neutrality of money, which means that. Group of answer choices changes in the money supply do not influence real variables.
Last updated: February 2, 2000
Note: These notes are preliminary and incomplete and they are not guaranteed to be free of errors. Please let me know if you find typos or other errors.
The Asset Market
Up to now we have covered (1) the labor market and the production function, where real wages, employment and potential output is determined, and (2) the market for goods and services, where the real interest rate and investment and saving are determined. Now we consider the market for financial assets (money and 'bonds') by focusing on the demand and supply of money in the economy. This will give us insights into other forces on interest rates - particularly those created by the Fed - and also on the ultimate determinants of inflation.
What is Money?
- Medium of exchange - barter is inefficient.
- Unit of account - money is the basic unit for measuring economic value.
- Store of value - money can be used to hold wealth.
- Low return (interest rate) - money pays no interest
- Low risk - money is a 'safe' asset in low inflation times
- High liquidity - money is the most liquid asset (money is accepted immediately for almost all transactions)
Definitions of monetary aggregates
| Symbol | Assets Included | Billions of dollars (1996) |
| C | Currency | $358.9 |
| M1 | Currency, demand deposits, traveler's checks, checkable deposits. | $1,095.3 |
| M2 | Currency, M1, overnight repos, eurodollars, money market deposit accounts, money market mutual funds, saving and small time deposits. | $3,761.1 |
In this class, when we talk about the nominal money supply we will generally be referring to the monetary aggregate M1. Hereafter, the symbol 'M' will denote M1.
The supply of money
The Federal Reserve Bank (Fed)
The Federal Reserve Bank (Fed) ultimately controls the supply of money in the economy. (How it does this and how the banking system works is detailed in the lectures on the Fed and Monetary Policy.) The Fed is the central bank for the U.S. and is a quasi-private entity (technically owned by private banks) created by the Federal Reserve Act in 1913. There are twelve regional Federal Reserve Banks across the country and the leadership of the system is conducted by the Board of Governors of the Federal Reserve System (Federal Reserve Board ). The Board consists of seven governors, appointed by the President to staggered fourteen-year terms. The President appoints one Board member as chairman - currently Allen Greenspan - for a term of four years. It is important to keep in mind that the Fed operates independently of the federal government. Congress and the President do not have direct control over the operations of the Fed.
How the Fed Controls the Money Supply
The Fed primarily controls the supply of money (M1) in the economy through what are called open market operations. These are the purchase and sale of government bonds by the Fed. The Fed operates the printing presses for the creation of currency. The Fed also owns a substantial amount of U.S. government bonds. When the Fed wants to increase the supply of money it performs an open market purchase of government bonds. That is, the Fed buys (by printing money) outstanding government bonds from the public or new government bonds from the Treasury (to finance the current deficit). This operations injects new cash into the economy. Conversely, when the Fed wants to decease the amount of money in the economy it performs an open market sale of government bonds. Here, the Fed sells some of its holdings of government bonds to the public in exchange for cash. This operation takes cash out of the economy.
Portfolio Allocation and the Demand for Assets
Portfolio theory tells us how individuals allocate their wealth among a number of financial assets (e.g. stocks, bonds, real estate, money). In general an individual's demand for assets is based on comparing the benefits of costs of holding different kinds of assets. These costs and benefits are functions of the following assets characteristics:
- Expected return - expected gain (or loss) from holding an asset over a particular investment horizon
- Risk - the degree of uncertainty in an asset's return
- Liquidity - the ease and quickness that an asset can be traded
An individual's demand for money is then based on the costs and benefits of holding money. As an asset, money has a very low expected return (it pays no interest), is very safe (the gov't guarantees its nominal value) and is the most liquid asset.
Simplifying assumptions
Since the general asset allocation problem involves many different kinds of assets with different risk and return characteristics we simplify this decision by assuming that there are only two kinds of financial assets in the economy.
- Money assets - low return, high liquidity and low risk. im = nominal interest rate on money assets (very low).
- Non-money assets (bonds) - higher return than on money assets and less liquidity. We assume that the risk associated with investing in bonds is not too high (think of government bonds as the generic non-money asset). Let i denote the nominal interest rate on non-money assets. Note that, by assumption, i > im. Also, recall that i = r +pe, where r denotes the real return on non-money assets and pe denotes expected inflation.
Behavorial Model for Money Demand
Our model for the demand for nominal money balances takes the following form
Md = P·Ld(Y, i)
where
- Md = demand for nominal money balances (demand for M1)
- Ld= demand for liquidity function
- P = aggregate price level (CPI or GDP deflator)
- Y = real income (real GDP)
- i = nominal interest rate on non-money assets
Discussion
- Nominal money demand is proportional to the price level. For example, if prices go up by 10% then individuals need 10% more money for transactions.
- As Y increases, desired consumption increases and so individuals need more money for the increased number of desired transactions. This is the liquidity demand for money.
- As the nominal interest rate on non-money assets (bonds), i, increases the opportunity cost of holding money increases and so the demand for nominal money balances decreases.
- Since i = r + pe, we can decompose the effects on an increase in i into real interest rate increases (holding expected inflation fixed) and expected inflation increases (holding the real interest rate fixed).
The demand for real balances
Since the demand for nominal balances is proportional to the aggregate price level, we can divide both sides of the nominal money demand equation by P. This gives the liquidity demand function or the demand for real balances function:
MD = Md/P = Ld(Y, i)
The left-hand-side of the above equation is the demand for nominal balances divided by the aggregate price level or the demand for real balances (the real purchasing power of money). The right-hand side is the liquidity demand function. The demand for real balances is decomposed into a transactions demand for money (captured by Y) and a portfolio demand for money (captured by i).
The real money demand function is graphed below:
Whenever income or expected inflation change the real money demand curves shifts. For example, if Y increases the real money demand function shifts up and right; if expected inflation increases the real money demand function shifts down and left.
Equilibrium in the money market
Real money demand and the real money supply as functions of the real interest rate are illustrated in the above graph. Real money demand is graphed holding fixed real income and expected inflation. The real money supply is equal to the nominal amount of M1, denoted M0, divided by the fixed aggregate price level, P0. It is assumed that the Fed does not alter the money supply based on the valued of the real interest rate. Therefore, the real money supply function is a vertical line in the graph with the real interest rate on the vertical axis and real money balances on the horizontal axis.
Notice that real money demand and real money supply intersect when the real interest rate is r0. This is the value of the real interest that equates money demand with the money supply and establishes equilibrium in the money market. When the money market is in equilibrium there are no economic forces acting on the economy to alter the real interest rate.
If the real interest rate were r1 then the demand for real balances would be greater than the fixed supply of real balances (as illustrated above). In this case we say there is an excess supply of money in the money market. Practically, what this means is that individuals are holding more money than they would like given the high real interest rate. Accordingly, individuals will attempt to rebalance their portfolios; i.e. they will try to get rid of money by buying bonds (our generic non-money asset). In doing so the demand for bonds increases and so the price of bonds increases. Because bond prices are inversely related to the interest rate on bonds, the increased price of bonds lowers the real return on bonds (holding expected inflation fixed). Therefore, the excess supply of money at r1 (dis-equilibrium in the money market) leads to economic forces that act to lower the real interest rate. These forces cease to operate when the real interest falls to r0 where the demand for real balances is equal to the supply of real balances.
Comparative statics
Increase in the nominal money supply (M)
Consider the money market initially in equilibrium at r = 6% as illustrated in the above graph.. Suppose the Fed increases the nominal money supply by an open market purchase of government bonds. This increases the money supply from M0 to M1. Holding the price level fixed, this increases the supply of real balances from M0/P0to M1/P0. If the real interest rate stays at 6% then the supply of real balances will be greater than the demand for real balances: there will be an excess supply of money in the money market. Consequently, individuals will try to get rid of the excess money by buying bonds which puts downward pressure on the real interest rate (holding expected inflation fixed). As r drops we move along the liquidity demand curve toward the new equilibrium at r = 5%.
Increase in the aggregate price level (P)
Consider the money market initially in equilibrium at r = 6% described in the graph below. Now suppose that the aggregate price level increases from P0 to P1. Holding the nominal money supply fixed, this reduces the supply of real balances from M0/P0 to M0/P1. If the real interest rate stays at 6% the supply of real balances will be less than the demand for real balances: there will be an excess demand for money. The excess demand for money will prompt individuals to sell bonds (demand for bonds falls) and so the real interest rate on bonds will rise. As r rises, we move up along the liquidity demand curve toward the new equilibrium at r = 7%.
Consider the money market in equilibrium at r = 6% as illustrated above. Suppose that current income (Y), which is the same as current output (GDP),. Increases from Y0 to Y1. This increases the transactions demand for money as so the real money demand curve shifts up and to the right. If the real interest rate stays at 6% there will be an excess demand for money which puts upward pressure on the real interest rate. As r increases, we move along the money demand curve up towad the new equilibrium at r = 8%.
26.1 The Quantity Theory of Money
Learning Objectives
After you have read this section, you should be able to answer the following questions.

- What is the quantity theory of money?
- What is the classical dichotomy?
- According to the quantity theory, what determines the inflation rate in the long run?
We begin by presenting a framework to highlight the link between money growth and inflation over long periods of time.The framework complements our discussion of inflation in the short run, contained in Chapter 25 'Understanding the Fed'. The quantity theory of moneyA relationship among money, output, and prices that is used to study inflation. is a relationship among money, output, and prices that is used to study inflation. It is based on an accounting identity that can be traced back to the circular flow of income. Among other things, the circular flow tells us that
nominal spending = nominal gross domestic product (GDP).Is Money Supply Nominal Or Real Energy
The “nominal spending” in this expression is carried out using money. While money consists of many different assets, you can—as a metaphor—think of money as consisting entirely of dollar bills. Nominal spending in the economy would then take the form of these dollar bills going from person to person. If there are not very many dollar bills relative to total nominal spending, then each bill must be involved in a large number of transactions.
The velocity of moneyNominal GDP divided by the money supply. is a measure of how rapidly (on average) these dollar bills change hands in the economy. It is calculated by dividing nominal spending by the money supply, which is the total stock of money in the economy:
If the velocity is high, then for each dollar, the economy produces a large amount of nominal GDP.
Using the fact that nominal GDP equals real GDP × the price level, we see that

And if we multiply both sides of this equation by the money supply, we get the quantity equationAn equation stating that the supply of money times the velocity of money equals nominal GDP., which is one of the most famous expressions in economics:
money supply × velocity of money = price level × real GDP.Let us see how these equations work by looking at 2005. In that year, nominal GDP was about $13 trillion in the United States. The amount of money circulating in the economy was about $6.5 trillion.In Chapter 24 'Money: A User’s Guide', we discussed the fact that there is no simple single definition of money. This figure refers to a number called “M2,” which includes currency and also deposits in banks that are readily accessible for spending. If this money took the form of 6.5 trillion dollar bills changing hands for each transaction that we count in GDP, then, on average, each bill must have changed hands twice during the year (13/6.5 = 2). So the velocity of money was 2 in 2005.
Toolkit: Section 31.27 'The Circular Flow of Income'
You can review the circular flow of income in the toolkit.
The Classical Dichotomy
So far, we have just written a definition. There are two steps that take us from this definition to a theory of inflation. First we use the quantity equation to give us a theory of the price level. Then we examine the growth rate of the price level, which is the inflation rate.
In macroeconomics we are always careful to distinguish between nominal and real variables:
- Nominal variablesA variable defined and measured in terms of money. are defined and measured in terms of money. Examples include nominal GDP, the nominal wage, the dollar price of a carton of milk, the price level, and so forth. (Most nominal variables are measured in monetary units, but some are just numbers. For example, the nominal interest rate tells you how many dollars you will obtain next year for each dollar you invest in an asset this year. It is thus measured as “dollars per dollar,” so it is a number.)
- All variables not defined or measured in terms of money are real variablesA variable defined and measured in terms other than money, often in terms of real GDP.. They include all the variables that we divide by a price index in order to correct for the effects of inflation, such as real GDP, real consumption, the capital stock, the real wage, and so forth. For the sake of intuition, you can think of these variables as being measured in terms of units of (base year) GDP (so when we talk about real consumption, for example, you can think about the actual consumption of a bundle of goods and services by a household). Real variables also include the supply of labor (measured in hours) and many variables that have no specific units but are just numbers, such as the velocity of money or the capital-to-output ratio of an economy.
Prior to the Great Depression, the dominant view in economics was an economic theory called the classical dichotomyThe dichotomy that real variables are determined independently of nominal variables.. Although this term sounds imposing, the idea is not. According to the classical dichotomy, real variables are determined independently of nominal variables. In other words, if you take the long list of variables used by macroeconomists and write them in two columns—real variables on the left and nominal variables on the right—then you can figure out all the real variables without needing to know any of the nominal variables.
Following the Great Depression, economists turned instead to the aggregate expenditure modelThe relationship between planned spending and output. to better understand the fluctuations of the aggregate economy. In that framework, the classical dichotomy does not hold. Economists still believe the classical dichotomy is important, but today economists think that the classical dichotomy only applies in the long run.
The classical dichotomy can be seen from the following thought experiment. Start with a situation in which the economy is in equilibrium, meaning that supply and demand are in balance in all the different markets in the economy. The classical dichotomy tells us that this equilibrium determines relative prices (the price of one good in terms of another), not absolute prices. We can understand this result by thinking about the markets for labor, goods, and credit.
Figure 26.2 'Labor Market Equilibrium' presents the labor market equilibrium. On the vertical axis is the real wage because households and firms make their labor supply and demand decisions based on real, not nominal, wages. Households want to know how much additional consumption they can get by working more, whereas firms want to know the cost of hiring more labor in terms of output. In both cases, it is the real wage that determines economic choices.
Now think about the markets for goods and services. The demand for any good or service depends on the real income of households and the real price of the good or service. We can calculate real prices by correcting for inflation: that is, by dividing each nominal price by the aggregate price level. Household demand decisions depend on real variables, such as real income and relative prices.If you have studied the principles of microeconomics, remember that the budget constraint of a household depends on income divided by the price of one good and on the price of one good in terms of another. If there are multiple goods, the budget constraint can be determined by dividing income by the price level and by dividing all prices by the same price level. The same is true for the supply decisions of firms. We have already argued that labor demand depends on only the real wage. Hence the supply of output also depends on the real, not the nominal, wage. More generally, if the firm uses other inputs in the production process, what matters to the firm’s decision is the price of these inputs relative to the price of its output, or—more generally—relative to the overall price level.If you have studied the principles of microeconomics, the condition that price equals marginal cost is used to characterize the output decision of a firm. What matters then is the price of the input, relative to the price of output.
What about credit markets? The supply and demand for credit depends on the real interest rate. This means that those supplying credit think about the return they receive on making loans in real terms: although the loan may be stated in terms of money, the supply of credit actually depends on the real return. The same is true for borrowers: a loan contract may stipulate a nominal interest rate, but the real interest rate determines the cost of borrowing in terms of goods. The supply of and demand for credit is illustrated in Figure 26.3 'Credit Market Equilibrium'.
Figure 26.3 Credit Market Equilibrium
The credit market equilibrium occurs at a quantity of credit extended (loans) and a real interest rate where the quantity supplied is equal to the quantity demanded.
Toolkit: Section 31.3 'The Labor Market', Section 31.24 'The Credit (Loan) Market (Macro)', and Section 31.8 'Correcting for Inflation'
You can review the labor market and the credit market, together with the underlying demand and supply curves, in the toolkit. You can also review how to correct for inflation.
The classical dichotomy has a key implication that we can study through a comparative statics exercise. Recall that in a comparative statics exercise we examine how the equilibrium prices and output change when something else, outside of the market, changes. Here we ask: what happens to real GDP and the long-run price level when the money supply changes? To find the answer, we begin with the quantity equation:
money supply × velocity of money = price level × real GDP.Previously we discussed this equation as an identity—something that must be true by the definition of the variables. Now we turn it into a theory. To do so, we make the assumption that the velocity of money is fixed. This means that any increase in the money supply must increase the left-hand side of the quantity equation. When the left-hand side of the quantity equation increases, then, for any given level of output, the price level is higher (equivalently, for any given value of the price level, the level of real GDP is higher).
What then changes when we change the money supply: output, prices, or both? Based on the classical dichotomy, we know the answer. Real variables, such as real GDP and the velocity of money, stay constant. A change in a nominal variable—the money supply—leads to changes in other nominal variables, but real variables do not change. The fact that changes in the money supply have no long-run effect on real variables is called the long-run neutrality of moneyThe fact that changes in the money supply have no long-run effect on real variables..
Toolkit: Section 31.16 'Comparative Statics'
You can find more details on how to conduct comparative static exercises in the toolkit.
How does this view of the effects of monetary policy fit with the monetary transmission mechanismA mechanism explaining how the actions of a central bank affect aggregate economic variables, in particular real GDP.?See Chapter 25 'Understanding the Fed'. The monetary transmission mechanism explains that the monetary authority affects aggregate spending by changing its target interest rate.
- The monetary authority changes interest rates.
- Changes in interest rates influence spending on durables by firms and households.
- Changes in spending influence aggregate spending through a multiplier effect.
Remember that the monetary authority changes interest rates through open-market operations. If it wants to boost aggregate spending, it does so by cutting interest rates, and it cuts interest rates by purchasing government bonds with money. An interest rate cut is equivalent to an increase in the supply of money, so the monetary transmission mechanism also teaches us that an increase in the supply of money leads to an increase in aggregate spending.There is one difference, unimportant here, which is that the monetary transmission mechanism does not necessarily suppose that the velocity of money is constant. The monetary transmission mechanism is useful when we want to understand the short-run effects of monetary policy. When studying the long run, it is easier to work with the quantity equation and to think about monetary policy in terms of the supply of money rather than interest rates.
Finally, a reminder: in the short run, the neutrality of money does not hold. This is because in the short run we assume stickiness of nominal wages and/or prices. In this case, changes in the nominal money supply will lead to changes in the real money supply. With sticky wages and/or prices, the classical dichotomy is broken.
Long-Run Inflation
We now use the quantity equation to provide us with a theory of long-run inflation. To do so, we use the rules of growth rates. One of these rules is as follows: if you have two variables, x and y, then the growth rate of the product (x × y) is the sum of the growth rate of x and the growth rate of y. We can apply this to the quantity equation:
money supply × velocity of money = price level × real GDP.The left side of this equation is the product of two variables, the money supply and the velocity of money. The right side is likewise the product of two variables. So we obtain
growth rate of the money supply + growth rate of the velocity of money= inflation rate + growth rate of output.We have used the fact that the growth rate of the price level is, by definition, the inflation rate.
Toolkit: Section 31.21 'Growth Rates'
You can review the rules of growth rates in the toolkit.

We continue to assume that the velocity of money is a constant.In fact, the velocity of money might also grow over time as a result of developments in the financial sector. Saying that the velocity of money is constant is the same as saying that its growth rate is zero. Using this fact and rearranging the equation, we discover that the long-run inflation rate depends on the difference between how rapidly the money supply grows and how rapidly output grows:
inflation rate = growth rate of money supply − growth rate of output.The long-run growth rate of output does not depend on the growth rate of the money supply or the inflation rate. We know this because long-run output growth depends on the accumulation of capital, labor, and technology. From our discussion of labor and credit markets, equilibrium in these markets is described by real variables. Equilibrium in the labor market depends on the real wage and not on any nominal variables. Likewise, equilibrium in the credit market tells us that the level of investment does not depend on nominal variables. Since the capital stock in any period is just the accumulation of past investment, we know that the stock of capital is also independent of nominal variables.
Therefore there is a direct link between the money supply growth rate and the inflation rate. The classical dichotomy teaches us that changes in the money supply do not affect the velocity of money or the level of output. It follows that any changes in the growth rate of the money supply will show up one-for-one as changes in the inflation rate. We say more about monetary policy later, but notice that there are immediate implications for the conduct of monetary policy:
- In a growing economy, there are more transactions taking place, so there is typically a need for more money to facilitate those transactions. Thus some growth of the money supply is probably desirable to match the increased income.
- If the monetary authorities want a stable price level—zero inflation—in the long run, then they should try to set the growth rate of the money supply equal to the (long-run) growth rate of output.
- If the monetary authorities want a low level of inflation in the long run, then they should aim to have the money supply grow just a little bit faster than the growth rate of output.
Keep in mind that this is just a theory. The quantity equation holds as an identity. But the assumption of constant velocity and the statement that long-run output growth is independent of money growth are assertions based on a body of theory. We now look at how well this theory fits the facts.
Key Takeaways
- The quantity theory of money states that the supply of money times the velocity of money equals nominal GDP.
- According to the classical dichotomy, real variables, such as real GDP, consumption, investment, the real wage, and the real interest rate, are determined independently of nominal variables, such as the money supply.
- Using the quantity equation along with the classical dichotomy, in the long run the inflation rate equals the rate of money growth minus the growth rate of output.
Checking Your Understanding
Real Nominal Inflation
- Is the real wage a nominal variable? What about the money supply?
- If velocity of money decreases by 2 percent and the money supply does not grow, can you say what will happen to nominal GDP growth? Can you say what will happen to inflation?