Popularity of index funds and ETFs driving down average costs: Morningstar

As assets continue to flow into index mutual funds, ETFs and institutional share classes, investors paid less in fund expenses in 2016 than ever before, said Morningstar, Inc., in its annual fund fee study. The asset-weighted average net expense ratio of all U.S. funds was 0.57% in 2016, down from 0.61% in 2015 and 0.65% three years ago. The asset-weighted average expense ratio was 0.17% for passive funds and 0.75% for active funds, Morningstar said in a release. "Investors have been voting with their feet for low-cost funds," said Patricia Oey, senior manager research analyst for Morningstar. (More: Low volatility funds live up to their name as market falls) The research firm said that while outflows from active funds reached a cumulative $586 billion in 2015 and 2016, they were all from expensive active funds. "Low-cost active funds saw positive, albeit small, inflows of $41 billion over the same time period," Ms. Oey said. U.S. equity funds have seen the biggest migration to passive from active funds, Morningstar said, with the former drawing in $458 billion of inflows and the latter experiencing $525 billion of outflows over the past three years. During the same time period, U.S. equity funds' asset-weighted average fees fell a cumulative 17% to 0.5%, the largest change of any asset class. Among fund families, Vanguard has the lowest asset-weighted average expense ratio at 0.11%, followed by SPDR State Street Global Advisors at 0.19% and Dimensional Fund Advisors at 0.36%. During the past three years, Vanguard's asset-weighted average fee declined 21%, the greatest decline among the 10 largest fund providers. (More: Best- and worst-performing equity mutual funds)