Measuring and Modelling Variation in the Risk-Return Trade-Off

74 Pages Posted: 7 Jan 2002

See all articles by Martin Lettau

Martin Lettau

University of California - Haas School of Business; Centre for Economic Policy Research (CEPR); National Bureau of Economic Research (NBER)

Sydney C. Ludvigson

New York University - Department of Economics; National Bureau of Economic Research (NBER)

Date Written: December 2001

Abstract

Are excess stock market returns predictable over time and, if so, at what horizons and with which economic indicators? Can stock return predictability be explained by changes in stock market volatility? How does the mean return per unit risk change over time? This chapter reviews what is known about the time-series evolution of the risk-return tradeoff for stock market investment, and presents some new empirical evidence using a proxy for the log consumption-aggregate wealth ratio as a predictor of both the mean and volatility of excess stock market returns. We characterize the risk-return tradeoff as the conditional expected excess return on a broad stock market index divided by its conditional standard deviation, a quantity commonly known as the Sharpe ratio. Our own investigation suggests that variation in the equity risk-premium is strongly negatively linked to variation in market volatility, at odds with leading asset pricing models. Since the conditional volatility and conditional mean move in opposite directions, the degree of countercyclicality in the Sharpe ratio that we document here is far more dramatic than that produced by existing equilibrium models of financial market behaviour, which completely miss the sheer magnitude of variation in the price of stock market risk.

Keywords: Sharpe ratio, expected returns, volatility, consumption

JEL Classification: G10, G12

Suggested Citation

Lettau, Martin and Ludvigson, Sydney C., Measuring and Modelling Variation in the Risk-Return Trade-Off (December 2001). Available at SSRN: https://ssrn.com/abstract=294902

Martin Lettau (Contact Author)

University of California - Haas School of Business ( email )

Haas School of Business
545 Student Services Building
Berkeley, CA 94720
United States
5106436349 (Phone)

HOME PAGE: http://faculty.haas.berkeley.edu/lettau/

Centre for Economic Policy Research (CEPR)

London
United Kingdom

National Bureau of Economic Research (NBER)

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Sydney C. Ludvigson

New York University - Department of Economics ( email )

19 West 4th Street, 6th floor
New York, NY 10012
United States
212-998-8927 (Phone)
212-995-4186 (Fax)

HOME PAGE: http://www.econ.nyu.edu/user/ludvigsons/

National Bureau of Economic Research (NBER)

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Do you have negative results from your research you’d like to share?

Paper statistics

Downloads
36
Abstract Views
3,328
PlumX Metrics