We review theory and evidence relating to herd behavior, payoff and reputational interactions, social learning, and informational cascades in capital markets. We offer a simple taxonomy of effects, and evaluate how alternative theories may help explain evidence on the behavior of investors,...

This paper models how imperfect memory affects the optimal continuity of policies. We examine the choices of a player (individual or firm) who observes previous actions but cannot remember the rationale for these actions. In a stable environment, the player optimally responds to memory loss with...

We provide a model with overconfident risk neutral investors, and therefore no risk premia, in which a price-based portfolio such as HML earns positive expected returns and loads on fundamental macroeconomic variables. Furthermore, loadings on such portfolios are proxies for mispricing, and...

We review extensive evidence about how psychological biases affect investor behavior and prices. Systematic mispricing probably causes substantial resource misallocation. We argue that limited attention and overconfidence cause investor credulity about the strategic incentives of informed market...

This paper offers a model in which asset rices reflect both covariance risk and misperceptions of firms' prospects, and in which arbitrageurs trade against mispricing. In equilibrium, expected returns are linearly related to both risk and mispricing measures (e.g., fundamental/price ratios)....

We document considerable return comovement associated with accruals after controlling for other common factors. An accrual-based factor-mimicking portfolio has a Sharpe ratio of 0.16, higher than that of the market factor or the SMB and HML factors of Fama and French (1993). According to...

We review extensive evidence about how psychological biases affect investor behavior and prices. Systematic mispricing probably causes substantial resource misallocation. We argue that limited attention and overconfidence cause investor credulity about the strategic incentives of informed market...

We analyze capital allocation in a conglomerate where divisional managers with uncertain abilities compete for promotion to CEO. A manager can sometimes gain by unobservably adding variance to divisional output. Capital rationing can limit this distortion, increase productive efficiency, and...

In our model, informed players decide whether or not to disclose, and observers allocate attention among disclosed signals, and toward reasoning through the implications of a failure to disclose. In equilibrium disclosure is incomplete, and observers are unrealistically optimistic. Nevertheless,...

We provide a model in which irrational investors trade based upon considerations that are not inherently related to fundamentals. However, because trading activity affects market prices, and because of feedback from security prices to cash flows, the irrational trades influence underlying cash...