Plan sponsors have a clear legal obligation to monitor the quality of investments offered to retirement investors in 401(k) plans.
While that part of fiduciaries' obligations is indisputable, a small body of academic research on what happens when an investment option is removed in favor of another has shown that the new funds fail to outperform, and sometimes underperform, the removed funds.
One paper, published in the Journal of Finance in 2016, found no evidence that consultants' recommendations to replace investments resulted in added value to plan sponsors and investors in retirement plans.
Or in other words, action taken from the legal obligation to monitor fund lineups did not result in better savings outcomes.
But new research from Morningstar is pushing back on the idea that investment menus are best served with a set-it-and-forget-it design.
Like previous research, Morningstar found that the decision to replace a fund is largely based on comparisons of five-year historical performance.
But unlike previous research, Morningstar found that replacement funds go on to outperform the replaced funds over the ensuing one and three-year time periods after the switch.
Plan monitoring not a futile exercise
"We think the breadth of our analysis is unmatched compared to the other research," said Jim Licato, vice president, product management for Morningstar Investment Management, which houses the firm's advisory services unit.
Licato, David Blanchett, head of retirement research at Morningstar, and Michael Finke, a CFA with the American College of Financial Services, tapped Morningstar's managed account platform to analyze nearly 3,500 fund replacements in 678 defined contribution plans over an eight-year period beginning in 2010.
Prior research was based on significantly smaller data sets; one 2007 study that found no performance improvement in replacement funds was based on a sample of 45 deleted investment options.
Morningstar's analysis compared funds within the same investment style of three investment categories: equity, bond, and allocation funds that blend both.
Not surprisingly, the replacement funds tended to have lower expense ratios than the replaced funds, better historical returns, and overall higher ratings from Morningstar.