Long Memory in Foreign Exchange Rates Revisited

: There has been recent evidence for long memory in the changes of foreign exchange spot rates that is captured by the fractionally integrated ARMA model. This paper extends these investigations in several directions. First, the estimation procedure allows for GARCH errors. Second, in addition to the total period from 1973 to 1990 three subperiods are analyzed. Third, for the US-Dollar spot rates of the Deutsche Mark and the Swiss Franc ARFIMAmodel selection and estimation results for various observation frequencies are compared to ARFIMA specifications and their parameter values that are obtained from temporal aggregation. As a result the evidence for weak long memory in the changes of US-Dollar exchange rates is confirmed. However, long memory appears to be a property attached to the US currency since the analysis of the Deutsche Mark/Swiss Franc spot rate changes does not reveal any long memory. KEYWORDS: time series analysis, long memory, ARFIMA models, GARCH models, foreign excha...