Reflections on the Efficient Market Hypothesis: 30 Years Later

Abstract

The evidence is overwhelming that active equity management is, in the words of Ellis (1998), a "loser's game." Switching from security to security accomplishes nothing but to increase transactions costs and harm performance. Thus, even if markets are less than fully efficient, indexing is likely to produce higher rates of return than active portfolio management. The most successful modern-day investor, Warren Buffett, sums up the advice in this paper with characteristic wisdom: "Most investors, both institutional and individual, will find that the best way to own common stocks ... is through an index fund that charges minimal fees. Those following this path are sure to beat the net results (after fees and expenses) of the great majority of investment professionals."

Keywords: Index funds, active portfolio management, mutual funds, market efficiency

JEL Classification: G11, G14, G29