We provide empirical evidence that deviations from the uncovered interest rate parity (UIP) condition display significant nonlinearities, consistent with theories based on transactions costs or limits to speculation. This evidence suggests that the forward bias documented in the literature may be less indicative of major market inefficiencies than previously thought. Monte Carlo experiments allow us to reconcile theseresults with the large empirical literature on the forward bias puzzle since we show that, if the true process of UIP deviations were of the nonlinear form we consider, estimation of conventional spot-forward regressions would generate the anomalies documented in previous research.

The sign of the correlation between equity returns and exchange rate returns can be positive or negative in theory. Using data for a broad set of forty-two countries, we find that exchange rate movements are in fact unrelated to differentials in country-level equity returns. Consequently, a trading strategy that invests in countries with the highest expected equity returns and shorts those with the lowest generates substantial returns and Sharpe ratios. These returns partially reflect compensation for global equity volatility risk, but significant excess returns remain after controlling for exposure to standard risk factors.