Fees for mutual funds and exchange-traded funds have been falling for years, but the decline accelerated in historic fashion in 2017, according to Morningstar. The average expense ratio for funds in 2017, when weighted for the amount the funds have in assets, was 0.52%. That represents a decline of 8% from the 2016 average. “This is the largest year-over-year decline we have recorded since we began tracking the trend in asset-weighted average fees in 2000,” wrote Patricia Oey, a senior fund analyst at Morningstar. “Consequently, we estimate that investors saved roughly $4 billion in fund expenses last year.” Read the original story from MarketWatch.