We analyze the performance of irrational investors, who mistake expected returns of assets in a multi-asset economy. Mistakes by probabilistically unsophisticated investors that a priori seem small lead to severe underperformance compared with rational investors, under general conditions. Our...

Correlations of equity securities have varied substantially over time and remain a source of continuing policy debate. This paper studies stock market correlations in an equilibrium model with heterogeneous risk aversion. In the model, preference heterogeneity causes countercyclical variations...

the long run mean and/or the persistence of expected inflation.

This paper analyzes portfolio diversification for nonlinear transformations of heavy-tailed risks. It is shown that diversification of a portfolio of convex functions of heavy-tailed risks increases the portfolio's riskiness if expectations of these risks are infinite. In contrast, for concave...

This paper analyzes portfolio diversification for nonlinear transformations of heavy-tailed risks. It is shown that diversification of a portfolio of convex functions of heavy-tailed risks increases the portfolio’s riskiness if expectations of these risks are infinite. In contrast, for...

We introduce costly internal capital into a standard insurance model, in which a risk-averse policyholder buys insurance from a risk-neutral insurer with limited liability. The unique optimal contract and internal capital lead to a strictly positive probability for insurer default. Some risks...

We show that the US residential single-family mortgage-origination market is highly concentrated once account is taken of the contractual coordination that arises from the correspondent- and warehouse-funding channels. We represent these channels as a network, using the flow of loans through...

Recent results in value at risk analysis show that, for extremely heavy-tailed risks with unbounded distribution support, diversification may increase value at risk, and that generally it is difficult to construct an appropriate risk measure for such distributions. We further analyze the...

We develop a tractable dynamic general equilibrium model of oligopolistic competition with a continuum of heterogeneous industries. Industries are exposed to aggregate and industry-specific productivity shocks. Firms in each industry set value-maximizing state-contingent markups, taking as given...

Recent research has suggested that natural selection in financial markets may be a very slow process, taking hundreds of years. We show in a general equilibrium model that it may be much faster in markets with large state spaces. In many cases, the time it takes to wipe out irrational investors...