Efficiency with Costly Information: A Study of Mutual Fund Performance, 1965–1984

Abstract

If information is costly to collect and implement, then it is efficient for trades by informed investors to occur at prices sufficiently different from full-information prices to compensate them for the cost of becoming informed. This notion is tested by evaluating investment performance in the mutual fund industry over a 20-year period. The study finds evidence that is consistent with optimal trading in efficient markets. Risk-adjusted returns in the mutual fund industry, net of fees and expenses, are comparable to returns available in index funds; and portfolio turnover and management fees are unrelated to fund performance.