Gonnella, though, cautions that the new information may not be enough and could even serve to confuse plan participants and employers. For instance, participants will have to add the hard-dollar expense from their quarterly statement with the investment expense they will need to calculate themselves – 401(k) providers are not required to explicitly state “you paid X dollars to the Y fund manager.”

“So unless a sponsor has a mechanism to calculate the average daily balance of the underlying investments throughout a calendar year, any well-meaning, manual fee calculation is usually inaccurate, not to mention time-consuming,” Gonnella said.

Meanwhile, ETFs still face hurdles in getting into the 401(k) space as many of retirement plans are geared toward mutual fund providers. For example, ETFs are traded on an exchange during normal market hours and incur commission fees on trades. The funds are also only traded in full shares, so some money may not be fully invested. [ETFs Face 401(k) Hurdles]

Critics have also been quick to point out that the quick tradability found in the ETF investment vehicle may encourage active day trading in retirement accounts. The naysayers believe that since the 401(k) plans are long-term investments, investors should only be limited to diversified, asset-class ETFs instead of specialized sector funds.

For more information on ETFs in 401(k)s, visit our 401(k) category.

Max Chen contributed to this article.