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Review of Finance Vol. 12 No. 3 2008

Equity Portfolio Diversification

William N. Goetzmann1; Alok Kumar2

1 Yale University 1 School of Management , · 2 University of Texas at Austin 2 McCombs School of Business ,

open access

Abstract

This study shows that U.S. individual investors hold under-diversified portfolios, where the level of under-diversification is greater among younger, low-income, less-educated, and less-sophisticated investors. The level of under-diversification is also correlated with investment choices that are consistent with over-confidence, trend-following behavior, and local bias. Furthermore, investors who over-weight stocks with higher volatility and higher skewness are less diversified. In contrast, there is little evidence that portfolio size or transaction costs constrains diversification. Under-diversification is costly to most investors, but a small subset of investors under-diversify because of superior information.

DOI
10.1093/rof/rfn005
Volume
12
Issue
3
Pages
433-463
Language
en
Sources
bibtex:phds-export.bib openalex crossref

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