By Vivian Yue, Stephanie Schmitt-Grohe, Martin Uribe and Seunghoon Na
This paper characterizes jointly optimal default and exchange-rate policy in a small open economy with limited enforcement of debt contracts and downward nominal wage rigidity. Under optimal policy, default occurs during contractions and is accompanied by large devaluations. The latter inflate away real wages thereby avoiding massive unemployment. Thus, the Twin Ds phenomenon emerges endogenously as the optimal outcome. By contrast, under fixed exchange rates, optimal default takes place in the context of large involuntary unemployment. Fixed-exchange-rate economies are shown to have stronger default incentives and therefore support less external debt than economies with optimally floating rates.
In other words, default is more likely to happen if a highly indebted economy joins a monetary union.