Real Exchange Rates and Real Interest Rates Differential: Evidence from Nigeria

The theoretical relationship of the long-run equilibrium between real exchange rates and interest rate differentials is essentially derived from the Purchasing Power Parity (PPP) and the uncovered interest parity. However, empirical evidence on this long-run relationship has rather been inconclusive. While several authors are able to establish the long-run relationship between real exchange rates and interest rate differentials other could not found this relationship. The reason for lack of relationship in some of the studies is as a result of omitted variables (Meese and Rogoff, 1988). Therefore, attempt is made in this study to evaluate this relationship between real exchange rate and interest rate differential for the case of Nigeria by controlling for foreign exchange reserves. The paper uses monthly data for the period 1993:1-2012:12 and applies Autoregressive Distributed Lags (ARDL) model. The estimates suggest the existence of long-run relationship between real exchange rate, interest rate differential and foreign exchange reserves. In the long run, the exchange rate coefficient has a positive effect on the foreign reserves. However, the effect of interest rate differential is negative and statistically significant. On the short run dynamics, the finding indicates a non-monotonic relationship between real exchange rate, interest rate differential and foreign exchange reserves. The out-of-sample forecast indicates a better forecast using ARMA model as all Theil coefficients are close zero for all the horizons used in the model.