Using asymmetric nonlinear smooth-transition GARCH(M) models for the period of 1926:01 - 1997:12, this paper shows that monthly excess returns on value-weighted market indexes exhibit a strong asymmetric reverting pattern; a negative return reverts more quickly, with a greater reverting...

We suggest that an unexpected volatility shock is an important risk factor to induce the intertemporal relation, and the conflicting findings on the relation could be attributable to an omitting variable bias resulting from ignoring the effect of an unexpected volatility shock on the relation....