We build a general equilibrium model to examine the implications of prospect theory for the disposition effect, asset prices, and trading volume. Diminishing sensitivity predicts a disposition effect, price momentum, a reduced return volatility, and a positive return-volume correlation. Loss aversion generally predicts the opposite. In calibrated economies, there is a nontrivial range of preference parameters for prospect theory to simultaneously explain the disposition effect, the momentum effect, and the equity premium puzzle. Our model is helpful for understanding a wide range of financial phenomena and it also suggests new testable predictions.

Theoretically, the implied cost of capital (ICC) is a good proxy for time-varying expected returns. We find that aggregate ICC strongly predicts future excess market returns at horizons ranging from one month to four years. This predictive power persists even in the presence of popular valuation ratios and business cycle variables, both in-sample and out-of-sample, and is robust to alternative implementations. We also find that ICCs of size and book-to-market portfolios predict corresponding portfolio returns.