Pricing currency options in the presence of time-varying volatility and non-normalities

Abstract

A new framework is developed for pricing currency options in the case where the distribution of exchange rate returns exhibits time-varying volatility and non-normalities. A forward-looking volatility structure is adopted whereby volatility is expressed as a function of currency returns over the life of the contract. Time to maturity and moneyness effects in volatility are also modelled. An analytical solution for the option price is obtained up to a one-dimensional integral in the real plane, enabling option prices to be computed efficiently and accurately. The proposed modelling framework is applied to European currency call options for the UK pound written on the US dollar, over the period October 1997–June 1998. The results show that pricing higher order moments improves both within-sample fit and out-of-sample prediction of observed option prices, as well as having important implications for constructing hedged portfolios and managing risk.