For many years after the Second World War most countries operated a system of fixed exchange rates. The external value of a currency was fixed in terms of the US$ and the value of the US$ itself was fixed in terms of gold. In effect, therefore, the values of the currencies were fixed in terms of gold. The ‘fixed’ rate was not absolutely rigid. The value of a currency was allowed to vary within a narrow band of 1 or 2% on each side of the ‘fixed’ rate or parity. For example, if the value of the NZ$ were fixed at NZ$1 = US$0.50, a permitted deviation of 2% would allow it to vary between NZ$1 = US$0.51 and NZ$1 = US$0.49. These limits are often described as ‘the ceiling’ and ‘the floor’. Central banks were responsible for maintaining the values of their currencies within the prescribed bands. They are able to do this by acting as buyers or sellers of the currency in the foreign exchange market. For this purpose each central bank must have a fund containing supplies of the home currency and foreign currencies.
The way in which the Reserve Bank of New Zealand can use its funds of currencies to influence the exchange rate can be explained by making use of the diagram below. Let us assume that the value of the NZ$ has been fixed at A and, initially, the market is in equilibrium at this exchange rate. The permitted band of fluctuation is PP1 and the value of the pound must be held within these limits. A large increase in imports now causes an increase in the supply of NZ$’s in the foreign exchange market. The supply curve moves from SS to S1S1 causing a surplus of NZ$’s at the ‘fixed’ rate (A). If no intervention takes place, the external value of the
NZ$ will fall to B which is below the permitted ‘floor’.
The Reserve Bank will be obliged to enter the market and buy NZ$. In doing so that will shift the demand curve to the right and raise the value of the NZ$ until it is once again within agreed limits. In the diagram below intervention by the Reserve Bank of NZ has raised the exchange rate to C.
When the Reserve Bank of New Zealand is buying NZ$’s, it will be using up its reserves of foreign currencies; when buying NZ$’s it exchanges foreign currencies for NZ$’s. ‘Supporting the NZ dollar’, that is, increasing the demand for NZ$’s, therefore leads to a fall in the nation’s foreign currency reserves. In the opposite situation where an increased demand for NZ$’s tends to lift the value of the NZ$ above the permitted ‘ceiling’, the central bank will hold down its value by selling NZ$’s. This will increase the supply of NZ$’s and lower the exchange rate. When the Reserve Bank is selling NZ$’s it will be increasing its holdings of foreign currencies.
The main argument for a fixed exchange rate is the same as that against a floating rate. A fixed rate removes a major cause for uncertainty in international transactions. Traders can quote prices which will be accepted with some degree of confidence; buyers know that they will not be affected by movements in the exchange rate. The risks associated with international trade are lessened and this should encourage more trade between nations and more international borrowing and lending.