We develop a q-theoretic model of investment under incomplete information that explains the link between idiosyncratic volatility and stock returns. When calibrated to match properties of the US business cycles as well as various firms and industry characteristics, the model generates a negative...

When investors have incomplete information, expected returns, as measured by an econometrician, deviate from those predicted by standard asset pricing models by including a term that is the product of the stock’s idiosyncratic volatility and the investors’ aggregated forecast errors. If...

We develop a model of firm investment under incomplete information that explains why idiosyncratic volatility and stock returns are related. When the unobserved state variable proxies for the business cycles, we show that a properly calibrated version of the model generates a negative relation...

We consider a pure exchange economy with incomplete information. Some agents in the economy display learning bias and over- or underreact to the arrival of new information. We study, by simulation, the distribution of irrational agents’ consumption shares. We find that over a reasonable...

We consider a pure exchange economy with incomplete information. Some agents display learning bias and over- or under-react to the arrival of new information. We show under which conditions biased agents survive over a finite horizon. We also study the distribution of irrational agents...

We consider a pure exchange economy where the drift of aggregate consumption is unobservable. Agents with heterogeneous beliefs and preferences act competitively on financial and goods markets. We discuss how equilibrium market prices of risk differ across agents, and in particular we discuss...

We consider a pure exchange economy with incomplete information. Some agents in the economy display learning bias and over- or underreact to the arrival of new information. We study, by simulation, the distribution of irrational agents' consumption shares. We find that over a reasonable horizon...