Analytic Equity Option Pricing with Stochastic Volatility

Abstract

We consider the Heston stochastic volatility model for equity options and use operator formalism and perturbation expansion techniques to derive a formal analytic expression for the Green's function (pricing kernel). This is expanded explicitly as a perturbation series in powers of the vol of vol up to second order and used to obtain an asymptotically accurate pricing formula for vanilla equity options, replicating results obtained previously by Ito and Malliavin techniques.