Debauchery and Original Sin: The Currency Composition of Sovereign Debt Charles Engel1 and JungJae Park2 September, 2021 Abstract We present a model that accounts for the “mystery of original sin”, and the surge in local currency borrowing by emerging economies in the recent decade. We quantitatively investigate the currency composition of sovereign debt in the presence of two types of limited enforcement frictions arising from a government’s monetary and debt policy: strategic currency debasement and default on sovereign debt. Local currency debt obligations act as a better consumption hedge against income shocks than foreign currency debt because their real value can be affected by monetary policy. However, this provides a government with more temptation to deviate from disciplined monetary policy, thus restricting borrowing in local currency more than in foreign currency. Our model predicts that a country with less credible monetary policy borrows mainly in foreign currency as a substitute for monetary credibility. An important extension demonstrates that in the presence of an expectational Phillips curve, local currency debt improves the ability of monetary policymakers to commit. JEL: E32, E44, F34 1 University of Wisconsin-Madison. Email:
[email protected]. 2Yonsei University. Email:
[email protected]. Charles Engel acknowledges support from the National Science Foundation, grant #MSN226099. JungJae Park is grateful for the financial support from the Ministry of Education of Singapore. This paper has been benefited from comments at numerous conferences and seminars. We thank Manuel Amador, Yan Bai, Javier Bianchi, Galina Hale, Dmitry Mukhin, and Pablo Ottonello for comments and discussion. 1. Introduction “Original sin” in the international finance literature refers to a situation in which emerging economy central governments are not able to borrow abroad in their own currency.