Abstract:
This article is devoted to maximization of HARA (hyperbolic absolute risk
aversion) utilities of the exponential Lévy switching processes on a finite
time interval via the dual method. The description of all $f$-divergence minimal
martingale measures and the expression of their Radon–Nikodým densities
involving the Hellinger and Kulback–Leibler processes are given. The optimal
strategies in progressively enlarged filtration for the maximization of HARA
utilities as well as the values of the corresponding maximal expected utilities
are derived. As an example, the Brownian switching model is presented with
financial interpretations of the results via the value process.