TY - JOUR
AU - Lettau, Martin
AU - Wachter, Jessica
TI - Why is Long-Horizon Equity Less Risky? A Duration-Based Explanation of the Value Premium
JF - National Bureau of Economic Research Working Paper Series
VL - No. 11144
PY - 2005
Y2 - February 2005
DO - 10.3386/w11144
UR - http://www.nber.org/papers/w11144
L1 - http://www.nber.org/papers/w11144.pdf
N1 - Author contact info:
Martin Lettau
Haas School of Business
University of California, Berkeley
545 Student Services Bldg. #1900
Berkeley, CA 94720-1900
Tel: 510/642-6349
Fax: 510/643-1412
E-Mail: lettau@haas.berkeley.edu
Jessica Wachter
Department of Finance
2300 SH-DH
The Wharton School
University of Pennsylvania
3620 Locust Walk
Philadelphia, PA 19104
Tel: 215/898-7634
Fax: 215/898-6200
E-Mail: jwachter@wharton.upenn.edu
AB - This paper proposes a dynamic risk-based model that captures the high expected returns on value stocks relative to growth stocks, and the failure of the capital asset pricing model to explain these expected returns. To model the difference between value and growth stocks, we introduce a cross-section of long-lived firms distinguished by the timing of their cash flows. Firms with cash flows weighted more to the future have high price ratios, while firms with cash flows weighted more to the present have low price ratios. We model how investors perceive the risks of these cash flows by specifying a stochastic discount factor for the economy. The stochastic discount factor implies that shocks to aggregate dividends are priced, but that shocks to the time-varying price of risk are not. As long-horizon equity, growth stocks covary more with this time-varying price of risk than value stocks, which covary more with shocks to cash flows. When the model is calibrated to explain aggregate stock market behavior, we find that it can also account for the observed value premium, the high Sharpe ratios on value stocks relative to growth stocks, and the outperformance of value (and underperformance of growth) relative to the CAPM.
ER -