We introduce the Homoscedastic Gamma [HG] model where the distribution of returns is characterized by its mean, variance and an independent skewness parameter under both measures. The model predicts that the spread between historical and risk-neutral volatilities is a function of the risk...

This paper studies asset markets in which ambiguity averse investors face Knightian uncertainty about expected payoffs. The same investors, however, might wish to resolve their uncertainty, although not risk, by just purchasing information. In these markets, uninformed and, hence, ambiguity...