In a continuous time stochastic economy, this paper considers the problem of
consumption and investment in a financial market in which the representative
investor exhibits a change in the discount rate. The investment opportunities
are a stock and a riskless account. The market coefficients and discount factor
switches according to a finite state Markov chain. The change in the discount
rate leads to time inconsistencies of the investor's decisions. The randomness
in our model is driven by a Brownian motion and Markov chain.
This paper considers the optimal portfolio selection problem in a dynamic
multi-period stochastic framework with regime switching. The risk preferences
are of exponential (CARA) type with an absolute coefficient of risk aversion
which changes with the regime. The market model is incomplete and there are two
risky assets: one tradable and one non-tradable. In this context, the optimal
investment strategies are time inconsistent. Consequently, the subgame perfect
equilibrium strategies are considered.