Estimation Error and Portfolio Optimization: A Resampling Solution

25 Pages Posted: 10 Sep 2015 Last revised: 29 Sep 2015

Date Written: 2007


Markowitz (1959) mean-variance (MV) portfolio optimization has been the practical standard for asset allocation and equity portfolio management for almost fifty years. However, it is known to be overly sensitive to estimation error in risk-return estimates and have poor out-of-sample performance characteristics. The Resampled Efficiency™ (RE) techniques presented in Michaud (1998) introduce Monte Carlo methods to properly represent investment information uncertainty in computing MV portfolio optimality and in defining trading and monitoring rules. This paper reviews and updates the literature on estimation error and RE portfolio optimization and rebalancing. We resolve several open issues and misunderstandings that have emerged since Michaud (1998). In particular, we show RE optimization to be a Bayesian-based generalization and enhancement of Markowitz’s solution.

Suggested Citation

Michaud, Richard O. and Michaud, Robert, Estimation Error and Portfolio Optimization: A Resampling Solution (2007). Available at SSRN: or

Richard O. Michaud (Contact Author)

New Frontier Advisors ( email )

155 Federal Street
Suite 1000
Boston, MA 02110
United States
617-482-1433 (Phone)
617-482-1434 (Fax)


Robert Michaud

Independent ( email )

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