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...

One of the most striking portfolio puzzles is the %u201Cdisposition effect%u201D: the tendency of individuals to sell stocks in their portfolios that have risen in value since purchase, rather than fallen in value. Perhaps the most prominent explanation for this puzzle is based on prospect...

We study equilibrium firm-level stock returns in two economies: one in which investors are loss averse over the fluctuations of their stock portfolio and another in which they are loss averse over the fluctuations of individual stocks that they own. Both approaches can shed light on empirical...

We examine the business model of traditional commercial banks in the context of their co-existence with shadow banks. While both types of intermediaries create safe "money-like" claims, they go about this in different ways. Traditional banks create safe claims by relying on deposit insurance,...

We use measures of neural activity provided by functional magnetic resonance imaging (fMRI) to test the "realization utility" theory of investor behavior, which posits that people derive utility directly from the act of realizing gains and losses. Subjects traded stocks in an experimental market...

We introduce the model of asset management developed in Gennaioli, Shleifer, and Vishny (2012) into a Solow-style neoclassical growth model with diminishing returns to capital. Savers rely on trusted intermediaries to manage their wealth (claims on capital stock), who can charge fees above costs...

Behavioral finance tries to make sense of financial data using models that are based on psychologically accurate assumptions about people's beliefs, preferences, and cognitive limits. I review behavioral finance approaches to understanding asset prices and trading volume, with particular...

We model a financial market in which investor beliefs are shaped by representativeness. Investors overreact to a series of good news, because such a series is representative of a good state. A few bad news do not change investor minds because the good state is still representative, but enough...

We present a standard model of financial innovation, in which intermediaries engineer securities with cash flows that investors seek, but modify two assumptions. First, investors (and possibly intermediaries) neglect certain unlikely risks. Second, investors demand securities with safe cash...