Deriving an optimal asset allocation hinges crucially on the quality of inputs used in the optimization. If the vector of expected returns and the covariance matrix are known with certainty, mean-variance optimization produces optimal portfolios. If, however, these parameters are estimated with...

This paper examines efficient allocations in economies where consumers exhibit heterogeneous smooth ambiguity preferences and face model uncertainty with a common set of identifiable models. Aggregate endowment is ambiguous. We characterize economies where the representative consumer is of the...

We theoretically and empirically study large-scale portfolio allocation problems when transaction costs are taken into account in the optimization problem. We show that transaction costs act on the one hand as a turnover penalization and on the other hand as a regularization, which shrinks the...