American Passport options in an exponential Lévy model

In this paper we examine the problem of valuing an exotic derivative known as the American passport option where the underlying is driven by a L\'evy process. The passport option is a call option on a trading account. We derive the pricing equation, using the dynamic programming principle, and prove that the option value is a viscosity solution of variational inequality. We also establish the comparison principle, which yields uniqueness and the convexity of the viscosity solution.