We present an extrapolative model of bubbles. In the model, many investors form their demand for a risky asset by weighing two signals—an average of the asset's past price changes and the asset's degree of overvaluation. The two signals are in conflict, and investors “waver” over time in...

We present an extrapolative model of bubbles. In the model, many investors form their demand for a risky asset by weighing two signals--an average of the asset's past price changes and the asset's degree of overvaluation. The two signals are in conflict, and investors "waver" over time in the...