Search Results
Report
The CAPM is alive and well
In empirical studies of the CAPM, it is commonly assumed that, (a) the return to the value-weighted portfolio of all stocks is a reasonable proxy for the return on the market portfolio of all assets in the economy, and (b) betas of assets remain constant over time. Under these assumptions, Fama and French (1992) find that the relation between average return and beta is flat. We argue that these two auxiliary assumptions are not reasonable. We demonstrate that when these assumptions are relaxed, the empirical support for the CAPM is very strong. When human capital is also included in measuring ...
Journal Article
The CAPM debate
This article describes the academic debate about the usefulness of the capital asset pricing model (the CAPM) developed by Sharpe and Lintner. First the article describes the data the model is meant to explain?the historical average returns for various types of assets over long time periods. Then the article develops a version of the CAPM and describes how it measures the risk of investing in particular assets. Finally the article describes the results of competing studies of the model's validity. Included are studies that support the CAPM (Black; Black, Jensen, and Scholes; Fama and ...
Journal Article
The simple analytics of commodity futures markets: do they stabilize prices? Do they raise welfare?
This paper uses a simple, graphical approach to analyze what happens to commodity prices and economic welfare when futures markets are introduced into an economy. It concludes that these markets do not necessarily make prices more or less stable. It also concludes that, contrary to common belief, whatever happens to commodity prices is not necessarily related to what happens to the economic welfare of market participants: even when futures markets reduce the volatility of prices, some people can be made worse off. These conclusions come from a series of models that differ in their assumptions ...
Working Paper
Ex-dividend price behavior of common stocks
This study examines common stock prices around ex-dividend dates. Such price data usually contain a mixture of observations - some with and some without arbitrageurs and/or dividend capturers active. Our theory predicts that such mixing will result in a nonlinear relation between percentage price drop and dividend yield - not the commonly assumed linear relation. This prediction and another important prediction of theory are supported empirically. In a variety of tests, marginal price drop is not significantly different from the dividend amount. Thus, over the last several decades, ...
Working Paper
Momentum Trading, Return Chasing and Predictable Crashes
We combine self-collected historical data from 1867 to 1907 with CRSP data from 1926 to 2012, to examine the risk and return over the past 140 years of one of the most popular mechanical trading strategies ? momentum. We find that momentum has earned abnormally high risk-adjusted returns ?a three factor alpha of 1 percent per month between 1927 and 2012 and 0.5 percent per month between 1867 and 1907 ? both statistically significantly different from zero. However, the momentum strategy also exposed investors to large losses (crashes) during both periods. Momentum crashes were predictable ? ...
Journal Article
The declining U.S. equity premium
This study demonstrates that the U.S. equity premium has declined significantly during the last three decades. The study calculates the equity premium using a variation of a formula in the classic Gordon stock valuation model. The calculation includes the bond yield, the stock dividend yield, and the expected dividend growth rate, which in this formulation can change over time. The study calculates the premium for several measures of the aggregate U.S. stock portfolio and several assumptions about bond yields and stock dividends and gets basically the same result. The premium averaged about 7 ...
Report
The conditional CAPM and the cross-section of expected returns
Most empirical studies of the static CAPM assume that betas remain constant over time and that the return on the value-weighted portfolio of all stocks is a proxy for the return on aggregate wealth. The general consensus is that the static CAPM is unable to explain satisfactorily the cross-section of average returns on stocks. We assume that the CAPM holds in a conditional sense, i.e., betas and the market risk premium vary over time. We include the return on human capital when measuring the return on aggregate wealth. Our specification performs well in explaining the cross-section of average ...
Journal Article
Why should older people invest less in stock than younger people?
Financial planners typically advise people to shift investments away from stocks and toward bonds as they age. The planners commonly justify this advice in three ways. They argue that stocks are less risky over a young person?s long investment horizon, that stocks are often necessary for young people to meet large financial obligations (like college tuition for their children), and that younger people have more years of labor income ahead with which to recover from the potential losses associated with stock ownership. This article uses economic reasoning to evaluate these three different ...
Report
Econometric evaluation of asset pricing models
We provide a brief review of the techniques that are based on the Generalized Method of Moments (GMM) and used for evaluating capital asset pricing models. We first develop the CAPM and multi-beta models and discuss the classical two-stage regression method originally used to evaluate them. We then describe the pricing kernel representation of a generic asset pricing model; this representation facilitates use of the GMM in a natural way for evaluating the conditional and unconditional versions of most asset pricing models. We also discuss diagnostic methods that provide additional insights.
Report
A contingent claim approach to performance evaluation
We show that valuing performance is equivalent to valuing a particular contingent claim on an index portfolio. In general the form of the contingent claim is not known and must be estimated. We suggest approximating the contingent claim by a series of options. We illustrate the use of our method by evaluating the performance of 130 mutual funds during the period 1968?82. We find that the relative performance rank of a fund is rather insensitive to the choice of the index, even though the actual value of the services of the portfolio manager depends on the choice of the index.