Rare Disasters, Tail-Hedged Investments, and Risk-Adjusted Discount Rates
What is the best way to incorporate a risk premium into the discount rate schedule for a real investment project with uncertain payoffs? The standard CAPM formula suggests a beta-weighted average of the return on a safe investment and the mean return on an economy-wide representative risky investment. Suppose, though, that the project constitutes a tail-hedged investment, meaning that it is expected to yield positive payoffs in catastrophic states of nature. Then the model of this paper suggests that what should be combined in a weighted average are not the two discount rates, but rather the corresponding two discount factors. This implies an effective discount rate schedule that declines over time from the standard CAPM formula down to the riskfree rate alone. Some simple numerical examples are given. Implications are noted for discounting long-term public investments and calculating the social cost of carbon in climate change.
|Date of creation:||Oct 2012|
|Contact details of provider:|| Postal: National Bureau of Economic Research, 1050 Massachusetts Avenue Cambridge, MA 02138, U.S.A.|
Web page: http://www.nber.org
More information through EDIRC
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Michael Greenstone & Elizabeth Kopits & Ann Wolverton, 2011.
"Estimating the Social Cost of Carbon for Use in U.S. Federal Rulemakings: A Summary and Interpretation,"
1106, Massachusetts Institute of Technology, Center for Energy and Environmental Policy Research.
- Michael Greenstone & Elizabeth Kopits & Ann Wolverton, 2011. "Estimating the Social Cost of Carbon for Use in U.S. Federal Rulemakings: A Summary and Interpretation," NBER Working Papers 16913, National Bureau of Economic Research, Inc.
- Gollier, Christian & Weitzman, Martin, 2009.
"How Should the Distant Future be Discounted When Discount Rates are Uncertain?,"
TSE Working Papers
09-107, Toulouse School of Economics (TSE).
- Gollier, Christian & Weitzman, Martin L., 2010. "How should the distant future be discounted when discount rates are uncertain?," Economics Letters, Elsevier, vol. 107(3), pages 350-353, June.
- Christian Gollier & Martin L. Weitzman, 2009. "How Should the Distant Future be Discounted when Discount Rates are Uncertain?," CESifo Working Paper Series 2863, CESifo Group Munich.
- Gollier, Christian & Weitzman, Martin, 2009. "How Should the Distant Future be Discounted When Discount Rates are Uncertain?," IDEI Working Papers 588, Institut d'Économie Industrielle (IDEI), Toulouse.
- Lucas, Robert E, Jr, 1978. "Asset Prices in an Exchange Economy," Econometrica, Econometric Society, vol. 46(6), pages 1429-45, November.
- Robert J. Barro, 2006.
"Rare Disasters and Asset Markets in the Twentieth Century,"
The Quarterly Journal of Economics,
Oxford University Press, vol. 121(3), pages 823-866.
- Barro, Robert, 2006. "Rare Disasters and Asset Markets in the Twentieth Century," Scholarly Articles 3208215, Harvard University Department of Economics.
- Ian Martin, 2010.
"The Valuation of Long-Dated Assets,"
NBER Working Papers
16219, National Bureau of Economic Research, Inc.
- R. Mehra & E. Prescott, 2010.
"The equity premium: a puzzle,"
Levine's Working Paper Archive
1401, David K. Levine.
When requesting a correction, please mention this item's handle: RePEc:nbr:nberwo:18496. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: ()
If references are entirely missing, you can add them using this form.