In this paper we consider the optimization problem of an agent who wants to
maximize the total expected discounted utility from consumption over an
infinite horizon. The agent is under obligation to pay a debt at a fixed rate
until he/she declares bankruptcy. At that point, after paying a fixed cost, the
agent will be able to keep a certain fraction of the present wealth, and the
debt will be forgiven. The selection of the bankruptcy time is taken to be at
the discretion of the agent. The novelty of this paper is that at the time of
bankruptcy the wealth process has a discontinuity, and that the agent continues
to invest and consume after bankruptcy. We show that the solution of a free
boundary problem satisfying some additional conditions is the value function of
the above optimization problem. Particular examples such as the logarithmic and
the power utility functions will be provided, and in these cases explicit forms
will be given for the optimal bankruptcy time, investment and consumption
processes.
Print date:
April 29, 2008