Ambiguity aversion alone does not explain the market nonparticipation puzzle. We show that in a rational expectations equilibrium model with a fund offering the risk-adjusted market portfolio (RAMP), ambiguity averse investors hold the fund and an information-based portfolio, and thus...

We provide the first tests to distinguish whether individual investors equally balance their overall portfolios (naïve portfolio diversification--NPD) or engage in naïve buying diversification (NBD)--equally balancing values in same-day purchases of multiple assets. We find NBD in purchases of...