Small-time expansions for state-dependent local jump–diffusion models with infinite jump activity

Abstract

In this article, we consider a Markov process {Xt}t⩾0, which solves a stochastic differential equation driven by a Brownian motion and an independent pure jump component exhibiting both state-dependent jump intensity and infinite jump activity. A second order expansion is derived for the tail probability P[Xt⩾x+y] in small time t, where x is the initial value of the process and y>0. As an application of this expansion and a suitable change of the underlying probability measure, a second order expansion, near expiration, for out-of-the-money European call option prices is obtained when the underlying stock price is modeled as the exponential of the jump–diffusion process {Xt}t⩾0 under the risk-neutral probability measure.