This paper gauges the relative contribution of risk aversion, inter-temporal substitution and taste shocks on postwar monthly US equity premia. The time-varying consumption, market, and taste risks involved in the Euler equations are recovered from a common factor GARCH process and the MLE are obtained by applying the Kalman filter. Empirically, (1) the market risk is the only source of risk that does not statistically affect the equity premia, and thus, the hypothesis that the coefficient of relative risk aversion corresponds to the reciprocal of the elasticity of inter-temporal substitution is not rejected; (2) the estimates are reasonable, so that the equity premium puzzle is circumvented; and (3) taste risks are quantitatively important in capturing excess returns movements.
