%0 Journal Article %A Ronald J. Surz %A Mitchell Price %T The Truth About Diversification by the Numbers %D 2000 %R 10.3905/joi.2000.319444 %J The Journal of Investing %P 93-95 %V 9 %N 4 %X Most of us have heard the statement “90% of available diversification is achieved with a 15-stock portfolio.” Very few, if any, of us behave as though we believe this statement, and there's good reason why—it's not true. This article lays out the truth about how many times it takes to obtain adequate diversification in a domestic equity portfolio. It's much more than 15. %U https://joi.pm-research.com/content/iijinvest/9/4/93.full.pdf