This paper studies the implications of the imperfect credibility of an exchange rate target zone on the term structure of forward premia. The relationship between spot and forward exchange rates of different maturities reflects the possibility of repeated realignments of the exchange rate band. The credibility of the commitment to the target zone implicit in forward market data can be extracted by estimating the model. Application to French/German data indicates that the model is capable of matching observed patterns of interest rate differentials during the EMS, while yielding estimates of the credibility parameters that accord with the experience of the FF/DM exchange rate during the 1980s.

An empirical model of time-varying realignment risk in an exchange rate target zone is developed. Expected rates of devaluation are estimated as the difference between interest race differentials and estimated expected rates of depreciation within the exchange rate band, using French Franc/Deutsche Mark data during the European Monetary System. The behavior of estimated expected rates of depreciation accord well with the theoretical model of Bertola-Svensson (1990) . We are also able to predict actual realignments with some success.

The purpose of this study is to analyze realignment expectations in the exchange rate mechanism of the European Monetary System, in particular with reference to the five year period (1987-1992) during which no realignments were done.

Devaluation expectations for the Swedish krona are estimated for the period 1982-1991 with several methods. First the "simplest test" is applied under either only the minimal assumption of "no positive minimum profit" or the additional assumption of uncovered interest parity. Then a more precise method suggested by Bertola and Svensson is used, in which expected rates of depreciation within the exchange rate band, estimated in several ways, are subtracted from interest rate differentials. In addition the probability density of the time of devaluations is estimated. Finally, estimated devaluation expectations are to some extent explained by a few macrovariables and parliament elections