The purpose of this paper is to characterize the changes in risk premium in the 1980s. A five-variable vector autoregressive model (VAR) is constructed to calculate a risk premium series in the foreign exchange market. The risk premium series is volatile and time-varying. The hypothesis of no risk premium is strongly rejected for the entire sample and each of the two subsamples considered. Various tests using the constructed risk premium series suggest that a risk premium existed but it was neither constant nor stable over subsamples and that its volatility was considerably reduced after October 1982.

The hypothesis that the forward rate is an unbiased predictor of the future spot rate has been rejected in many empirical studies. The rejection of this hypothesis could occur because market behavior is inconsistent with rational-expectations or because there exists a risk premium. Equations describing the forward premium and the change in the exchange rate are estimated jointly, and tests of both the rational-expectations and no-risk-premium hypotheses are conducted. Empirical estimates, obtained using quarterly data for the yen-dollar exchange rate, reject the rational-expectations hypothesis and suggest that there exists a time-varying risk premium.