Many tests of asset pricing models address only the pricing predictions - but these pricing predictions rest on portfolio choice predictions which seem obviously wrong. This paper suggests a new approach to asset pricing and portfolio choices, based on unobserved heterogeneity. This approach...

We present a general equilibrium model in which heterogeneous investors choose among bonds, stocks, and an Index Fund holding the market portfolio. We show that, under standard assumptions, an equilibrium exists. We then derive predictions for equilibrium asset prices, investor behavior, and...