Heterogeneous Expectations and Exchange Rate Dynamics

This paper presents a continuous-time model of exchange rates relying not only on macroeconomic factors but also having a market microstructure component. The driving macroeconomic factor is the interest rate differential, while the market microstructure element is described by the expectations of boundedly rational portfolio managers who use a weighted average of the expectations of fundamentalists and chartists. Within this framework, the different roles of the macroeconomic factors and market microstructure elements on the determination of the exchange rate are examined explicitly. We show that this simple model generates very complicated market behaviour, including the existence of multiple steady state equilibria, the deviations of the market exchange rate from the fundamental, and market fluctuations. Numerical simulation of the corresponding stochastic version of the model shows that the model is able to generate typical time series and volatility clustering patterns observed in exchange rate markets.