Uniform Integrability of a Single Jump Local Martingale with State-Dependent Characteristics

Author(s):  
Michael Schatz ◽  
Didier Sornette
2010 ◽  
Vol 2010 ◽  
pp. 1-27
Author(s):  
José E. Figueroa-López ◽  
Jin Ma

Motivated by the so-called shortfall risk minimization problem, we consider Merton's portfolio optimization problem in a non-Markovian market driven by a Lévy process, with a bounded state-dependent utility function. Following the usual dual variational approach, we show that the domain of the dual problem enjoys an explicit “parametrization,” built on a multiplicative optional decomposition for nonnegative supermartingales due to Föllmer and Kramkov (1997). As a key step we prove a closure property for integrals with respect to a fixed Poisson random measure, extending a result by Mémin (1980). In the case where either the Lévy measure ν of Z has finite number of atoms or ΔSt/St−=ζtϑ(ΔZt) for a process ζ and a deterministic function ϑ, we characterize explicitly the admissible trading strategies and show that the dual solution is a risk-neutral local martingale.


Sign in / Sign up

Export Citation Format

Share Document