RARE DISASTERS AND EXCHANGE RATES∗ Emmanuel Farhi Xavier Gabaix Harvard, CEPR and NBER NYU, CEPR and NBER August 26, 2015 Abstract We propose a new model of exchange rates, based on the hypothesis that the possibility of rare but extreme disasters is an important determinant of risk premia in asset markets. The probability of world disasters as well as each country’s exposure to these events is time-varying. This creates joint fluctuations in exchange rates, interest rates, options, and stock markets. The model accounts for a series of major puzzles in exchange rates: excess volatility and exchange rate disconnect, forward premium puzzle and large excess returns of the carry trade, and comovements between stocks and exchange rates. It also makes empirically successful signature predictions regarding the link between exchange rates and telltale signs of disaster risk in currency options. JEL codes: G12, G15. ∗
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[email protected]. We are indebted to the editor and two referees for detailed and helpful suggestions. Mohsan Bilal, Igor Cesarec, Alex Chinco, Sam Fraiberger, Aaditya Iyer and Cheng Luo provided excellent research assistance. For helpful comments, we thank partici- pants at various seminars and conferences, and Fernando Alvarez, Robert Barro, Nicolas Coeurdacier, Daniel Cohen, Mariano Croce, Alex Edmans, François Gourio, Stéphane Guibaud, Hanno Lustig, Matteo Maggiori, Anna Pavlova, Ken Rogoff, José Scheinkman, John Shea, Hyun Shin, Andreas Stathopoulos, Adrien Verdelhan, Jessica Wachter. We thank the NSF (SES-0820517) for support. 1 I. Introduction We propose a new model of exchange rates, based on the hypothesis of Rietz (1988) and Barro (2006) that the possibility of rare but extreme disasters is an important determinant of risk premia in asset markets.