In a lecture presented in 2004, John Bogle, founder of the Vanguard Group, documented a direct and substantial relationship between management costs and mutual fund returns. Stratifying all funds by expense ratio, from lowest to highest, he reported the following 10-year average annual returns by quartile: 10.7 percent, 9.8 percent, 9.5 percent, and 7.7 percent. A presumption of market rationality would lead one to expect that investors demanded reduced fees in response to this negative correlation. According to Bogle, however, the average equity fund’s expense ratio was on a long-run rise, which represented a gain for mutual fund operators but an aggregate loss for the consumers they served. Read more