Valuing Foreign Exchange Rate Derivatives with a Bounded Exchange Process†

Foreign exchange rates have been subjected to periods of tighter or looser controls as various political and economic forces have waxed and waned. When currencies were backed by gold there were fixed exchange rates. In 1973 floating exchange rates were adopted though many countries did try to keep their currency values within certain ranges. More recently the European Economic Community formalized this practice. Free-floating exchange rates might be well characterized by the lognormal distribution which is standard in option pricing. However, this is probably a poor approximation for exchange rates which are kept within some range by the actions of one or both governments or central banks. This paper develops a model which can be used to value options and other derivative contracts when the underlying exchange rate is bounded in a fixed range (a, b). Methods for pricing both European and American style options are developed.