  We consider a stochastic financial incomplete market where the price
processes are described by a vector-valued semimartingale that is possibly
nonlocally bounded. We face the classical problem of utility maximization from
terminal wealth, with utility functions that are finite-valued over
$(a,\infty)$, $a\in\lbrack-\infty,\infty)$, and satisfy weak regularity
assumptions. We adopt a class of trading strategies that allows for stochastic
integrals that are not necessarily bounded from below. The embedding of the
utility maximization problem in Orlicz spaces permits us to formulate the
problem in a unified way for both the cases $a\in\mathbb{R}$ and $a=-\infty$.
By duality methods, we prove the existence of solutions to the primal and dual
problems and show that a singular component in the pricing functionals may also
occur with utility functions finite on the entire real line.
