To raise the price of foreign currency, the central bank simply buys foreign currency with
domestic currency; this reduces the supply of foreign currency on the foreign exchange market,
strengthening the foreign currency and weakening the domestic currency. The supply of foreign
currency shifts to the left and the exchange rate increases to the desired new peg, Ef1, as shown
in Figure 18.7. The resulting increase in the foreign reserves and the ensuing increase in the
monetary base can also be observed on the central bank’s balance sheet on the right side of
Figure 18.7.
We can also analyze the effect of a devaluation within the Mundell–Fleming framework. In
Chapter 17, we demonstrated that a devaluation results in a downward shift of the BP curve.
Now we add the new concept that, if the economy starts from a BP=0 equilibrium, the
devaluation can only happen if the central bank intervenes. The intervention, consisting in an
accumulation of foreign reserves (RES increases), causes an increase in the money supply (as
the monetary base, MB, increases). So both the BP and the LM curves shift out with a
devaluation. Figure 18.8 shows the two shifts.
The devaluation has also a third impact: it improves the current account and stimulates the
economy. This is represented by a rightward shift of the IS curve as exports increase and
imports are discouraged by the higher price of foreign currency. All three shifts result in a new
equilibrium corresponding to an economic expansion from Y0 to Y1.
Will this new peg be permanent? Is it a better peg for the economy? What is the impact on the
trade partners and their reactions? These are further questions that the model does not address.
In the second case, the devaluation is seen as performing a correction. Indeed, competitive
devaluation might be a thing of the past, but corrective devaluations have not been uncommon in
recent times