Optimal consumption and portfolio selection with Epstein-Zin utility under general constraints

Abstract

In this paper, we investigate the consumption-investment problem for an investor with Epstein-Zin utility under general constraints. In an incomplete market, we impose closed, not necessarily convex, constraints on strategies and characterize optimal consumption and investment strategies via backward stochastic differential equations (BSDEs). Due to the stochastic environment of the market, the solution to this BSDE is unbounded and thereby the BMO argument breaks down. We use the Lyapunov function to show a certain local martingale is a martingale and complete our proof by the martingale optimal principle. Finally, an explicit model is given to illustrate the main result.