Real exchange rate targeting and macroeconomic instability

Using an optimizing model of a small open economy, this paper studies the macroeconomic effects of PPP rules whereby the government increases the devaluation rate when the real exchange rate—defined as the price of tradables in terms of nontradables—is below its long-run level and reduces the devaluation rate when the real exchange rate is above its long-run level. The paper shows that the mere existence of such a rule can generate aggregate instability due to self-fulfilling expectations. The result is shown to obtain in both flexible- and sluggish-price environments.