The rule it issued yesterday is known as 408(b)(2) and requires service providers such as Fidelity, Vanguard, T.

FORBES: Will We Ever Find Out What We Pay In Retirement Fees?

In addition to the lawsuits against plan sponsors, cases have been brought against 401(k) plan service providers, such as Fidelity, Principal Life, John Hancock, Nationwide and ING.

FORBES: Time For Workers To Demand The 401(k) Plans They Deserve: Here's A Model

Banks can do a lot of things that Fidelity can't, like issue loans and service small businesses.

FORBES: Magazine Article