Do Exchange Rates Move In Line With Uncovered Interest Parity

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.

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

For about three decades until the Global Financial Crisis (GFC), Covered Interest Parity (CIP) appeared to hold quite closely—even as a broad macroeconomic relationship applying to daily or weekly data. Not only have CIP deviations significantly increased since the GFC, but potential macrofinancial drivers of the variation in CIP deviations have also become significant. The variation in CIP deviations seems to be associated with multiple factors, not only regulatory changes. Most of these do not display a uniform importance across currency pairs and time, and some are associated with possible temporary considerations (such as asynchronous monetary policy cycles).

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.

This paper presents a rule for foreign exchange interventions (FXI), designed to preserve financial stability in floating exchange rate arrangements. The FXI rule addresses a market failure: the absence of hedging solution for tail exchange rate risk in the market (i.e. high volatility). Market impairment or overshoot of exchange rate between two equilibria could generate high volatility and threaten financial stability due to unhedged exposure to exchange rate risk in the economy. The rule uses the concept of Value at Risk (VaR) to define FXI triggers. While it provides to the market a hedge against tail risk, the rule allows the exchange rate to smoothly adjust to new equilibria. In addition, the rule is budget neutral over the medium term, encourages a prudent risk management in the market, and is more resilient to speculative attacks than other rules, such as fixed-volatility rules. The empirical methodology is backtested on Banco Mexico’s FXIs data between 2008 and 2016.

Recent research has found that the Taylor-rule fundamentals have power to forecast changes in U.S. dollar exchange rates out of sample. Our work casts some doubt on that claim. However, we find strong evidence of a related in-sample anomaly. When we include U.S. inflation in the well-known uncovered interest parity regression of the change in the exchange rate on the interest-rate differential, we find that the inflation variable is highly significant and the interest-rate differential is not. Specifically, high U.S. inflation in one month forecasts dollar appreciation in the subsequent month. We introduce a model in which a Taylor rule determines monetary policy, but in which not only monetary shocks but also liquidity shocks drive nominal interest rates. This model can potentially account for the empirical findings.