Portfolio allocation problems between risky and ambiguous assets

This paper considers a portfolio allocation problem between a risky asset and an ambiguous asset, and investigates how greater ambiguity aversion influences the optimal proportion invested in the two assets. We derive several sufficient conditions under which greater ambiguity aversion decreases the optimal proportion invested in the ambiguous asset. Furthermore, we consider an international diversification problem as an application and show that ambiguity aversion partially resolves the home bias puzzle.