Retirement plans will have to tell participants about legal, accounting and recordkeeping fees, and they also will have to explain any amounts that can be taken out of participants’ accounts.

Officials at the U.S. Department of Labor have included that requirement in a final rule that affects fee and expense reporting for 401(k) plans and other types of plans that resemble 401(k) plans.

The rule, developed by the department’s Employee Benefits Security Administration (EBSA), should help participants make better apples-to-apples comparisons of plan expenses and investment options, officials say.

The new 401(k) plan fee reporting rule is set to take effect Dec. 19.

The rule will apply to 401(k)-type plans for plan years beginning on or after Nov. 1, 2011; and for calendar year plans starting Jan. 1, 2012.

“We’ve given a sufficiently long effective date to allow the industry and plan administrators time to adjust to the changes, Phyllis Borzi, the Labor Department assistant secretary in charge of EBSA, said during a press briefing.

A plan will have to give general information about how the plan is structured and how it works, provide a a list investment options, and describe any “brokerage window” that participants can use to

buy investments not on the plan’s own menu.

In addition to requiring a plan to break out administrative expenses such as legal and accounting fees separately, the plan will have to describe the fees participants must pay to complete steps such as taking out a plan loan or having a qualified domestic relations order processed.

The fee disclosures must be given to participants on or before the day they’re entitled to make their investment decision, and every year thereafter, Borzi said.

Plan participants must get statements at least quarterly, whether or not administrative or individual fees will be charged to or deducted from participants’ accounts, Borzi says.

Plans must show investment returns for 1-year, 5-year and 10-year periods for variable-return plan investment options and the annual rate of return and investment term for fixed-return options.

A plan statement also must detail total operating plans expenses, expressed as a percentage of the assets and as a dollar amount for each $1,000 invested, and stipulate any shareholder fees, Borzi said.

The states must include a plain-English glossary.