Limited Stock Market Participation and Asset Prices in a Dynamic Economy

Abstract

We present a consumption-based heterogeneous agent model that explains the equity premium puzzle and many associated asset pricing phenomena. The success of the model relies on a combination of limited stock market participation with uninsurable income risk and borrowing constraints. The two latter frictions - as shown by the early authors - generate a precautionary saving demand for tradable assets such as one-period discount bonds, and thus lower the risk-free rate. However, there is no precautionary saving demand for stocks because of limited stock market participation; therefore, our model generates a sizeable equity premium. Also, in the presence of borrowing constraints, the shareholder's consumption growth or the pricing kernel of stocks mirrors his income growth, which is volatile and mean-reverting. Stock prices, therefore, exhibit excess volatility as well as predictability. Moreover, the model predicts that stock market volatility is a U-shaped function of the price-dividend ratio, which helps explain the 'perverse' negative risk-return tradeoff documented in the literature. The argument for a leverage effect is thus not always valid; stock return is negatively related to contemporaneous conditional volatility mainly because of a volatility feedback effect.