Portfolio Choice, Liquidity Constraints and Stock Market Mean Reversion

This paper solves numerically for the optimal consumption and portfolio choice of an infinitely lived investor facing short-sales and borrowing constraints, undiversifiable labor income risk and a predictable time varying equity premium. The investor aggressively times the market while positive correlation between permanent earnings shocks and stock return innovations generates a substantial hedging demand for the riskless asset. Moreover, a speculative increase in savings arises when stock returns are expected to be high and conversely when future returns are expected to be low. Small information/optimization costs can make it optimal for an investor to assume i.i.d. excess stock returns both because liquidity constraints can be frequently binding and because households can smooth idiosyncratic earnings shocks using a small buffer stock of wealth.