Openness and Real Exchange Rate Volatility: In Search of an Explanation

The puzzle that real exchange rates are less volatile in open economies is an important challenge to exchange rate theory. Adjustment of domestic prices to nominal exchange rate movements can account for only a small proportion of this effect. Real and nominal shocks display no obvious correlation with openness. It is shown here that real effective exchange rates are more strongly mean-reverting in more open economies, even after controlling for exchange rate regime effects. This is predicted by the theory of current account sustainability, because of its emphasis on ratios to GDP rather than to trade flows.