Demand, Supply, and Equilibrium in the Money Market
We have discussed the role of supply and demand in the money market, and we have seen how it has an effect on interest rates as well. Here, you will learn how transfer costs and expectations can affect demand. What is Keynes' theory with regard to the relationship between investment in bonds and money?
Effects of Changes in the Money Market
Changes in the Money Supply
Now suppose the market for money is in equilibrium and the Fed changes the money supply. All other things unchanged, how will this change in the money supply affect the equilibrium interest rate and aggregate demand, real GDP, and the price level?
Suppose the Fed conducts open-market operations in which it buys bonds. This is an example of expansionary monetary policy. The impact of Fed bond purchases is illustrated in Panel (a) of Figure 25.10 "An Increase in the Money Supply". The Fed's purchase of bonds shifts the demand curve for bonds to the right, raising bond prices to Pb2. As we learned, when the Fed buys bonds, the supply of money increases. Panel (b) of Figure 25.10 "An Increase in the Money Supply" shows an economy with a money supply of M, which is in equilibrium at an interest rate of r1. Now suppose the bond purchases by the Fed as shown in Panel (a) result in an increase in the money supply to M′; that policy change shifts the supply curve for money to the right to S2. At the original interest rate r1, people do not wish to hold the newly supplied money; they would prefer to hold nonmoney assets. To reestablish equilibrium in the money market, the interest rate must fall to increase the quantity of money demanded. In the economy shown, the interest rate must fall to r2 to increase the quantity of money demanded to M′.
Figure 25.10 An Increase in the Money Supply
The Fed increases the money supply by buying bonds, increasing the demand for bonds in Panel (a) from D1 to D2 and the price of bonds to Pb2. This corresponds to an increase in the money supply to M′ in Panel (b). The interest rate must fall to r2 to achieve equilibrium. The lower interest rate leads to an increase in investment and net exports, which shifts the aggregate demand curve from AD1 to AD2 in Panel (c). Real GDP and the price level rise.
The reduction in interest rates required to restore equilibrium to the market for money after an increase in the money supply is achieved in the bond market. The increase in bond prices lowers interest rates, which will increase the quantity of money people demand. Lower interest rates will stimulate investment and net exports, via changes in the foreign exchange market, and cause the aggregate demand curve to shift to the right, as shown in Panel (c), from AD1 to AD2. Given the short-run aggregate supply curve SRAS, the economy moves to a higher real GDP and a higher price level.
Open-market operations in which the Fed sells bonds - that is, a contractionary monetary policy - will have the opposite effect. When the Fed sells bonds, the supply curve of bonds shifts to the right and the price of bonds falls. The bond sales lead to a reduction in the money supply, causing the money supply curve to shift to the left and raising the equilibrium interest rate. Higher interest rates lead to a shift in the aggregate demand curve to the left.
As we have seen in looking at both changes in demand for and in supply of money, the process of achieving equilibrium in the money market works in tandem with the achievement of equilibrium in the bond market. The interest rate determined by money market equilibrium is consistent with the interest rate achieved in the bond market.