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An Empirical Bayes Approach to Efficient Portfolio Selection

Published online by Cambridge University Press:  06 April 2009

Abstract

When portfolio optimization is implemented using the historical characteristics of security returns, estimation error can degrade the desirable properties of the investment portfolio that is selected. Given the problem of estimation risk, it is natural to formulate rules of portfolio selection within a Bayesian framework. In this framework, portfolio selection is based on maximization of expected utility conditioned on the predictive distribution of security returns. Most researchers have addressed the problem of estimation risk by asserting a noninformative diffuse prior that reduces the detrimental effect of estimation risk, but does not directly reduce estimation error. Portfolio performance can be improved by specifying an informative prior that reduces estimation error. An informative prior that all securities have identical expected returns, variances, and pairwise correlation coefficients is asserted. This informative prior reduces estimation error by drawing the posterior estimates of each security's expected return, variance, and pairwise correlation coefficients toward the average return, average variance, and average correlation coefficient, respectively, of all the securities in the population. The amount that each of these parameters is drawn toward its grand mean depends upon the degree to which the sample is consistent with the informative prior. This empirical Bayes method is shown to select portfolios whose performance is superior to that achieved, given the assumption of a noninformative prior or by using classical sample estimates.

Type
Research Article
Copyright
Copyright © School of Business Administration, University of Washington 1986

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References

REFERENCES

[1]Anderson, T. W.An Introduction to Multivariate Statistical Analysis. New York: John Wiley (1958).Google Scholar
[2]Ando, A., and Kaufman, G. M.. “Bayesian Analysis of the Independent Multinomial Process—Neither Mean nor Precision Known.” Journal of the American Statistical Association, 60 (03 1965), –347–353.Google Scholar
[3]Barry, C. B.Portfolio Analysis under Uncertain Means, Variances, and Covariances.” Journal of Finance, 29 (05 1974), 515522.CrossRefGoogle Scholar
[4]Barry, C. B., and Winkler, R. L.. “Nonstationarity and Portfolio Choice.” Journal of Financial and Quantitative Analysis, 11 (06 1976), 217235.CrossRefGoogle Scholar
[5]Bawa, V. S.; Brown, S. J.; and Klein, R. W.. Estimation Risk and Optimal Portfolio Choice, Studies in Bayesian Econometrics Bell Laboratories Series. New York: North Holland (1979).Google Scholar
[6]Brown, S. J. “Optimal Portfolio Choice under Uncertainty: A Bayesian Approach.” Unpublished Ph.D. diss., Univ. of Chicago, (1976).Google Scholar
[7]Chen, C.-F.Bayesian Inference for a Normal Dispersion Matrix and Its Application to Stochastic Multiple Regression Analysis.” Journal of the Royal Statistical Society, 41 (1979), 235248.Google Scholar
[8]Dempster, A. P.; Laird, N. M.; and Rubin, D. B.. “Maximum Likelihood from Incomplete Data via the EM Algorithm.” Journal of the Royal Statistical Society, 39 (1977), 138.Google Scholar
[9]Dempster, A. P.Elements of Continuous Multivariate Analysis. Cambridge, MA: Addison-Wesley (1969).Google Scholar
[10]Fama, E. F.Foundations of Finance: Portfolio Decisions and Security Prices. New York: Basic Books (1976).Google Scholar
[11]Frankfurter, G.; Phillips, H.; and Seagle, J.. “Bias in Estimating Portfolio Alpha and Beta Scores.” Review of Economics and Statistics, 56 (08 1976), 412414.CrossRefGoogle Scholar
[12]Kalymon, B. A.Estimation Risk in the Portfolio Selection Model.” Journal of Financial and Quantitative Analysis, 6(01 1971), 559582.CrossRefGoogle Scholar
[13]Klein, R. W., and Bawa, V. S.. “The Effect of Estimation Risk on Optimal Portfolio Choice.” Journal of Financial Economics, 3 (06 1976), 215231.CrossRefGoogle Scholar
[14]Klein, R. W., and Bawa, V. S.. “The Effect of Limited Information and Estimation Risk on Optimal Portfolio Diversification.” Journal of Financial Economics, 5 (08 1977), 89111.CrossRefGoogle Scholar
[15]Mao, J., and Saradal, C.. “A Decision Theory Approach to Portfolio Selection.” Management Science, 12 (04 1966), 323339.CrossRefGoogle Scholar
[16]Markowitz, H.Portfolio Selection.” Journal of Finance, 7 (03 1952), 7791.Google Scholar
[17]Press, S. James. Applied Multivariate Analysis. Malabar, FL: Robert E. Krieger Publ. (1982).Google Scholar
[18]Sharpe, W. F.A Simplified Model for Portfolio Analysis.” Management Science, 9 (01 1963), 277293.CrossRefGoogle Scholar
[19]Wilks, S. S.Sample Criteria for Testing Equality of Means, Equality of Variances, and Equality of Covariances in a Normal Multivariate Distribution.” Annals of Mathematical Statistics, 17 (09 1946), 257281.CrossRefGoogle Scholar
[20]Winkler, R. L.Bayesian Models for Forecasting Future Security Prices.” Journal of Financial and Quantitative Analysis, 8 (06 1973), 387406.CrossRefGoogle Scholar
[21]Winkler, R. L., and Barry, C. B.. “A Bayesian Model for Portfolio Selection and Revision.” Journal of Finance, 30 (03 1975), 179192.CrossRefGoogle Scholar