362 MODEL SELECTION AND HEDGING OF FINANCIAL DERIVATIVES 505101520253035404520% 15% 10% 5% 0% 5% 10% 15% 20%Gamma errorVolga errorVanna errorTotal errorFigure 18.2The hedging error probability density function obtained by
assuming that the additional claim has the same expiry (1 year) as the
option to hedge but different strike (K=1). The trader uses a
stochastic volatility model. All errors are expressed as a percentage
of the initial cost of the option5.005.0010.0015.0020.0025.0030.0040% 30% 20% 10% 0% 10% 20%Gamma errorVolga errorVanna errorTotal errorFigure 18.3The hedging error probability density function obtained by
assuming that the additional claim has the same strike (K=0.975) as the
option to hedge but different expiry (2 years). The trader uses a
stochastic volatility model. All errors are expressed as percentage
of the initial cost of the optionWe study two different cases. First we assume that we choose forDa liq-
uid at-the-money option that has the same expiry as the option to hedge (i.e.
a one-year call). In Figure 18.2 we show the hedging error coming from the
Gamma, the Volga and the Vanna terms separately, as well as the total error.