Efficiency with costly information: a reinterpretation of evidence from managed portfolios

We investigate the informational efficiency of mutual fund performancefor the period 1965-84. Results are shown to be sensitive tothe measurement of performance chosen. We find that returnson S&P stocks, returns on non-S&P stocks, and returnson bonds are significant factors in performance assessment.Once we correct for the impact of non-S&P assets on mutualfund returns, we find that mutual funds do not earn returnsthat justify their information acquisition costs. This is consistentwith results for prior periods.