Exchange Rates And Uncovered Interest Differentials

We estimate an empirical model of exchange rates with transitory and permanent monetary shocks. Using monthly post-Bretton-Woods data from the United States, the United Kingdom, and Japan, we report four main findings: First, there is no exchange rate overshooting in response to either temporary or permanent monetary shocks. Second, a transitory increase in the nominal interest rate causes appreciation, whereas a permanent increase in the interest rate causes short-run depreciation. Third, transitory increases in the interest rate cause short-run deviations from uncovered interest-rate parity in favor of domestic assets, whereas permanent increases cause deviations against domestic assets. Fourth, permanent monetary shocks explain the majority of short-run movements in nominal exchange rates.

Ex-post deviations from uncovered interest parity (UIP) – realized differences between dollar returns on identical assets of different currencies – equal the real interest differential plus real exchange rate growth. Among industrialized countries, UIP deviations are largely explained by unanticipated real exchange rate growth, but among developing countries, real interest differentials are “where the action is.” This observation is due to the greater variability of inflation in developing countries, but may also stem from higher and more variable risks and capital controls in these countries. Also, among developing countries with moderate inflation, offsetting comovements of real interest differentials and real exchange growth support the sticky-price hypothesis.

The Uncovered Interest Parity (UIP) puzzle has remained a moot point since it first circulated economic discourse in 1984 and, despite a number of attempts at a solution, the UIP puzzle and other anomalies in Exchange Rate Economics continue to perplex

Originally published in 1994. This work investigates seasonal fluctuations of US and British short term nominal interest rates, the dollar-sterling exchange rate and short term interest rate differentials between the US and Britain during the period 1883-1913. It finds that during the pre-World War Gold Standard seasonal movements in exchange rates did not tend to offset the seasonal fluctuations in interest rate differentials. It presents a model to explain the fluctuations and outlines two specific empirical investigations, considering the results in the light of more recent historical periods as well.

The well-known uncovered interest parity puzzle arises from the empirical regularity that, among developed country pairs, the high interest rate country tends to have high expected returns on its short term assets. At the same time, another strand of the literature has documented that high real interest rate countries tend to have currencies that are strong in real terms -- indeed, stronger than can be accounted for by the path of expected real interest differentials under uncovered interest parity. These two strands -- one concerning short-run expected changes and the other concerning the level of the real exchange rate -- have apparently contradictory implications for the relationship of the foreign exchange risk premium and interest-rate differentials. This paper documents the puzzle, and shows that existing models appear unable to account for both empirical findings. The features of a model that might reconcile the findings are discussed.

Using an adaptation of the Uncovered Interest Parity (UIP) condition, this paper analyzes the drivers behind the large, symmetric exchange rate swings observed during the financial crisis of 2008-2010. Employing a Nelson-Siegel model, we estimate yield curves and decompose the exchange rate movements into changes we attribute to monetary policy and a residual. We find that the depreciation phase of the currencies in our sample was largely dominated by safe-haven effects rather than carry trade activity or other return considerations. For some countries, however, the appreciation that began at the end of 2008 seems largely to reflect downward movement in the cumulative revisions to nominal forward differentials, suggesting carry trade.

This paper reexamines some unsettled theoretical and empirical issues regarding the relationship between nominal exchange rates and interest rate differentials and provides a model for the behavior of exchange rates in the long run, where interest rates are determined in the bond market. The model predicts that an increase in the interest rate differential appreciates the home currency. We test the model for the U.S. dollar against the Deutsche mark, the British pound, the Japanese yen, and the Canadian dollar. The first two pairs of exchange rates—for which purchasing power parity seems to hold—display a strong relationship with interest rate differentials.

According to uncovered interest rate Parity (UIP), the expected relative change in an exchange rate is equal to the difference between interest rates between the two currencies. Empirically, UIP is frequently rejected. In this paper, we examine whether exchange rates have at least any tendency to move in the direction predicted by UIP and whether exchange rates tend to move more in line with UIP in periods with large interest rate differentials.

This Paper tests for uncovered interest parity (UIP) using daily data for twenty-three developing and developed countries through the crisis-strewn 1990s. We find that UIP works better on average in the 1990s than in previous eras in the sense that the slope coefficient from a regression of exchange rate changes on interest differentials yields a positive coefficient (which is sometimes insignificantly different from unity). UIP works systematically worse for fixed and flexible exchange rate countries than for crisis countries, but we find no significant differences between rich and poor countries. Finally, we find evidence that varies considerably across countries and time, but is usually weakly consistent with an effective 'interest rate defense' of the exchange rate.

This paper provides an overview of the uncovered interest parity assumption. It traces the history of the interest parity concept, summarizes evidence on the empirical validity of uncovered interest parity, and discusses different interpretations of the evidence and the implications for macroeconomic analysis. The uncovered interest parity assumption has been an important building block in multiperiod models of open economies, and although its validity is strongly challenged by the empirical evidence, at least at short time horizons, its retention in macroeconomic models is supported on pragmatic grounds by the lack of much empirical support for existing models of the exchange risk premium.