The consumption beta theorem of Breeden makes the expected return on any asset a function only of its covariance with changes in aggregate consumption. It is shown that the theorem is more robust than was indicated by Breeden. The theorem obtains even if one deletes Breeden's assumptions that...

The market portfolio is in one sense the least important portfolio to provide to investors. In an J-agent one-period stochastic endowment economy, where preferences are quadratic, a social-welfare-minded contract designer would never create a contract that would allow trading the market...

The efficient markets hypothesis has dominated modern research on asset prices. Asset prices and their intrinsic values differ in inefficient financial markets but difficulties in the measurement of intrinsic value greatly complicate market efficiency tests. Reflections on the measurement of...

These notes discuss three aspects of dynamic factor pricing (i.e., APT) models. The first one is that diversifiable idiosyncratic risk is unpredictable in a no-arbitrage world. The second feature is that the conditional factor loadings or betas on the common factors are approximately constant...

Real stock prices seem to overreact to changes in long-term interest rates. That is, real stock prices drop when long-term interest rates rise (and rise when they fall) more than would be implied by a rational expectations present value model where expectations are based on a vector...