The SEC's executive compensation disclosure requirements have been confusing at best to the boards that grapple with them. Soon companies will have another challenging disclosure hurdle: transparency in 401(k) fees.

Over the last several months, lawmakers have been tweaking HR 3185, Rep. George Miller's (D-CA) bill requiring plans to disclose the fees they charge workers in defined contribution plans. Although no one knows exactly what the final legislation will look like (there's a Senate version of the bill as well), and the onus of understandable fee disclosure will fall largely on plan providers, the new requirements will create more work and greater costs for employers.

401(k) fees have become an urgent concern for legislators such as Miller for three compelling reasons: defined benefit plans have gone the way of the dinosaur so people rely more heavily on 401(k)s for retirement income; the downward spiral of real estate values has reduced wealth for millions of Americans; and the market downturn has battered retirement savings.

Fees for administrative expenses, investments management, transaction costs, etc. can take a big bite out of workers' savings. Some fees are fair and necessary, some are questionable -- and hidden.

Under current disclosure requirements, workers lack important information about fees they are paying, says the General Accounting Office (GAO). In fact, because of weak disclosure requirements, 80 percent of workers don't know that fees are taken out of their accounts, according to the GAO, which also says that a 1 percent increase in fees would cut retirement income by almost 20 percent after 20 years and 30 percent over 30 years.

HR 3185 doesn't mandate the fees that service providers can charge: It just requires them to disclose in clear and simple terms all the fees they charge plan participants. It would also require employers to offer at least one low-cost index fund in their plan.

Critics of the legislation say it could lead to such high costs that some companies would stop offering 401(k)s or pass those costs on to plan participants. They also argue that employees would favor the least expensive investment options when they may not be the best choices.

The Profit Sharing and 401(k) Council of America believes that the bill as it is currently written could place fiduciaries in a difficult situation -- that they could be charged with the responsibility for evaluation of more information than service providers are actually required to give them.

I wouldn't be surprised if some finance executives who have fiduciary responsibility for their company's 401(k) plan don't have a firm grip on current fees. That could be even more of a dangerous position in the future.