The requirement of positive marginal utility only makes it possible to derive a restricted twofund separation theorem for portfolio selection problems replacing the original separation theorem of Cass and Stiglitz (1970). We use our findings for a re-examination of the bias-in-beta problem in...

This paper studies a model of the distribution of income under bounded needs. Utility derived from any given good reaches a bliss point at a finite consumption level of that good. On the other hand, introducing new varieties always increases utility. It is assumed that each variety is owned by a...