A Lone Ranger of the 401(k)s

The arithmetic could not be simpler. The more fees you pay in your 401(k) plan, the less cash you’ll have for retirement.

Still, fees hidden from view can make it hard for 401(k) holders to find out what they are paying. Plan sponsors, usually an employer, have a fiduciary duty to safeguard workers’ retirement accounts. But sponsors don’t always push providers like mutual funds to reduce fees or cut costs.