This paper extends Merton’s continuous time (instantaneous) mean-varianceanalysis and the mutual fund separation theory. Given the existence of a Marko-vian state price density process, the optimal portfolios from concave utility max-imization are instantaneously mean-variance efficient...

We study the equilibrium pricing sects of a sentiment for pessimism. Pessimism has the form of Knightian model uncertainty aversion for a neighborhood of indistinguishable model specifications that are constrained in their relative entropy from a given reft ence model. We fully characterise the...