Mixture-Averse Preferences and Heterogeneous Stock Market Participation

To study intertemporal decisions under risk, we develop a new recursive model of non-expected-utility preferences. The main axiom of our analysis is called mixture aversion, as it captures a dislike of probabilistic mixtures of lotteries. Our representation for mixture-averse preferences can be interpreted as if an individual optimally selects her risk attitude from some feasible set. The representation includes special cases where the choice of risk attitude takes the form of an optimal selection of a reference point. We analyze the implications of the model for both insurance and investment decisions. The main application of the paper shows that mixture-averse preferences can generate endogenous heterogeneity in equilibrium stock market participation, even when consumers have identical preferences and even among wealthy households.