IDEAS home Printed from https://ideas.repec.org/p/ysm/somwrk/ysm236.html
   My bibliography  Save this paper

Equity Portfolio Diversification

Author

Listed:
  • Alok Kumar

    (Mendoza College of Business)

  • William N. Goetzmann

    (Yale University, School of Management)

Abstract

In this paper we examine the portfolios of more than 40,000 equity investment accounts from a large discount brokerage during a six year period (1991-96) in recent U.S. capital market history. Using the historical performance for the equities in these accounts, we find that a vast majority of investors in our sample are under-diversified. A cross-sectional examination of diversification reveals that young and active investors, and investors in low income and non-professional categories hold the least diversified portfolios. Over time, the average degree of diversification has improved but these improvements result primarily from changes in the correlation structure of the US equity market. Nonetheless, improved portfolio diversification has a considerable impact on the composition and performance of investor portfolios.

Suggested Citation

  • Alok Kumar & William N. Goetzmann, 2001. "Equity Portfolio Diversification," Yale School of Management Working Papers ysm236, Yale School of Management.
    • Handle: RePEc:ysm:somwrk:ysm236
    as

    Download full text from publisher

    File URL: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=287998
    Download Restriction: no
    ---><---

    Other versions of this item:

    References listed on IDEAS

    as
    1. Huberman, Gur, 2001. "Familiarity Breeds Investment," The Review of Financial Studies, Society for Financial Studies, vol. 14(3), pages 659-680.
    2. Blume, Marshall E & Friend, Irwin, 1975. "The Asset Structure of Individual Portfolios and Some Implications for Utility Functions," Journal of Finance, American Finance Association, vol. 30(2), pages 585-603, May.
    3. Cohn, Richard A, et al, 1975. "Individual Investor Risk Aversion and Investment Portfolio Composition," Journal of Finance, American Finance Association, vol. 30(2), pages 605-620, May.
    4. John Heaton & Deborah Lucas, 2000. "Portfolio Choice and Asset Prices: The Importance of Entrepreneurial Risk," Journal of Finance, American Finance Association, vol. 55(3), pages 1163-1198, June.
    5. Merton, Robert C, 1987. "A Simple Model of Capital Market Equilibrium with Incomplete Information," Journal of Finance, American Finance Association, vol. 42(3), pages 483-510, July.
    6. Perraudin, William R. M. & Sorensen, Bent E., 2000. "The demand for risky assets: Sample selection and household portfolios," Journal of Econometrics, Elsevier, vol. 97(1), pages 117-144, July.
    7. De Bondt, Werner F. M., 1998. "A portrait of the individual investor," European Economic Review, Elsevier, vol. 42(3-5), pages 831-844, May.
    8. R. S. Uhler & J. G. Cragg, 1971. "The Structure of the Asset Portfolios of Households," The Review of Economic Studies, Review of Economic Studies Ltd, vol. 38(3), pages 341-357.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Guiso, Luigi & Sodini, Paolo, 2013. "Household Finance: An Emerging Field," Handbook of the Economics of Finance, in: G.M. Constantinides & M. Harris & R. M. Stulz (ed.), Handbook of the Economics of Finance, volume 2, chapter 0, pages 1397-1532, Elsevier.
    2. Abrahamson, Martin, 2016. "“Rookies to the stock market: A portrait of new shareholders”," Research in International Business and Finance, Elsevier, vol. 38(C), pages 565-576.
    3. Kumar, Alok, 2007. "Do the diversification choices of individual investors influence stock returns?," Journal of Financial Markets, Elsevier, vol. 10(4), pages 362-390, November.
    4. Laurent E. Calvet & Paolo Sodini, 2014. "Twin Picks: Disentangling the Determinants of Risk-Taking in Household Portfolios," Journal of Finance, American Finance Association, vol. 69(2), pages 867-906, April.
    5. Giannetti, Mariassunta & Simonov, Andrei, 2003. "Which Investors Fear Expropriation? Evidence from Investors' Stock Picking," CEPR Discussion Papers 3843, C.E.P.R. Discussion Papers.
    6. Camille Magron & Maxime Merli, 2012. "Stocks repurchase and sophistication of individual investors," Working Papers of LaRGE Research Center 2012-02, Laboratoire de Recherche en Gestion et Economie (LaRGE), Université de Strasbourg.
    7. Laurent E. Calvet & John Y. Campbell & Paolo Sodini, 2007. "Down or Out: Assessing the Welfare Costs of Household Investment Mistakes," Journal of Political Economy, University of Chicago Press, vol. 115(5), pages 707-747, October.
    8. Richard Ochmann, 2014. "Differential income taxation and household asset allocation," Applied Economics, Taylor & Francis Journals, vol. 46(8), pages 880-894, March.
    9. Francisco Gomes & Michael Haliassos & Tarun Ramadorai, 2021. "Household Finance," Journal of Economic Literature, American Economic Association, vol. 59(3), pages 919-1000, September.
    10. Luigi Guiso & Tullio Jappelli, 2008. "Financial Literacy and Portfolio Diversification," Economics Working Papers ECO2008/31, European University Institute.
    11. Karagiannidis, Iordanis & Vozlyublennaia, Nadia, 2016. "Limits to mutual funds' ability to rely on mean/variance optimization," Journal of Empirical Finance, Elsevier, vol. 37(C), pages 282-292.
    12. Nikolai Roussanov, 2010. "Diversification and Its Discontents: Idiosyncratic and Entrepreneurial Risk in the Quest for Social Status," Journal of Finance, American Finance Association, vol. 65(5), pages 1755-1788, October.
    13. William N. Goetzmann & Massimo Massa & Andrei Simonov, 2004. "Portfolio Diversification and City Agglomeration," NBER Working Papers 10343, National Bureau of Economic Research, Inc.
    14. Xie, Jun & Yang, Chunpeng, 2013. "Shouldn't all eggs be putted in one basket? A portfolio model based on investor sentiment and inertial thinking," Economic Modelling, Elsevier, vol. 35(C), pages 682-688.
    15. Holmes, Marionette & Park, Timothy A., 2001. "Modeling Financial Asset Demands Of Small Agribusiness Firms: A Portfolio Theory Approach," 2001 Annual meeting, August 5-8, Chicago, IL 20461, American Agricultural Economics Association (New Name 2008: Agricultural and Applied Economics Association).
    16. Phelim Boyle & Lorenzo Garlappi & Raman Uppal & Tan Wang, 2012. "Keynes Meets Markowitz: The Trade-Off Between Familiarity and Diversification," Management Science, INFORMS, vol. 58(2), pages 253-272, February.
    17. John Y. Campbell, 2006. "Household Finance," Journal of Finance, American Finance Association, vol. 61(4), pages 1553-1604, August.
    18. Daniel Barth, 2018. "The Costs and Beliefs Implied by Direct Stock Ownership," Management Science, INFORMS, vol. 64(11), pages 5263-5288, November.
    19. Barasinska, Nataliya & Schäfer, Dorothea & Stephan, Andreas, 2012. "Individual Risk Attitudes and the Composition of Financial Portfolios: Evidence from German Household Portfolios," EconStor Open Access Articles and Book Chapters, ZBW - Leibniz Information Centre for Economics, vol. 52(1), pages 1-14.
    20. Lu, Xiaomeng & Zhang, Yong & Zhang, Yixing & Wang, Lin, 2020. "Can investment advisors promote rational investment? Evidence from micro-data in China," Economic Modelling, Elsevier, vol. 86(C), pages 251-263.

    More about this item

    Keywords

    Portfolio Diversification; Idiosyncratic Risk; Equity Market Correlation; Individual Investor Behavior;
    All these keywords.

    JEL classification:

    • G12 - Financial Economics - - General Financial Markets - - - Asset Pricing; Trading Volume; Bond Interest Rates
    • G11 - Financial Economics - - General Financial Markets - - - Portfolio Choice; Investment Decisions

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:ysm:somwrk:ysm236. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: the person in charge (email available below). General contact details of provider: https://edirc.repec.org/data/smyalus.html .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.