Finding Hidden 401(k) Fees

The Department of Labor has estimated that a one-percentage-point difference in annual 401(k) fees reduces a participant's retirement balance by approximately 28% over a 35-year career. That's not a rounding error — it's the difference between a comfortable retirement and one that falls short. And yet, a survey by AARP found that more than 80% of plan participants had no idea how much their plan was charging them.

For plan sponsors, the stakes are even higher. Under ERISA, you have a legal fiduciary obligation to ensure that every dollar your plan pays in fees is “reasonable.” That obligation extends to fees you can't easily see — costs embedded in fund expense ratios, paid between providers, or buried in transaction schedules most sponsors never request.

This guide covers the four categories of hidden 401(k) fees that plan sponsors most commonly miss — and exactly where to find them.

Fee #1: Transaction and Service Fees

Unlike recordkeeping or advisor fees, which are charged on a regular schedule, transaction and service fees are triggered by specific plan events. Because they don't show up on a regular invoice, many plan sponsors never add them up — and providers don't volunteer the total.

Common service fees include:

• Loan initiation fees: Charged when a participant takes a loan from their account. Industry averages run $75–$175 per loan.
• Distribution and withdrawal fees: Assessed when funds are disbursed at separation or retirement. Typically $50–$100 per distribution.
• Plan amendment fees: Charged when the plan document is updated for regulatory changes or design modifications.
• Form 5500 preparation fees: Some providers bill separately for preparing the annual government filing. The industry average for these transaction fees combined is approximately $975 per year.
• Plan termination fees: If you decide to move to a new provider, some recordkeepers charge a termination fee that can run into thousands of dollars.

These fees are often paid by participants directly from their accounts, meaning they reduce participant balances without ever appearing on the plan sponsor's invoice. Your 408(b)(2) fee disclosure is required to list these, but they may be expressed as a rate schedule rather than an estimated annual cost — making comparison difficult.

What to do: Request a complete fee schedule from your recordkeeper that lists every transaction fee. Then estimate an annual total based on your plan's typical loan and distribution activity. If competitors charge zero for these events, that difference belongs in your benchmark.

Fee #2: 12b-1 Fees (Advisor Distribution Trails)

In 1980, the SEC created Rule 12b-1, which allows mutual funds to use shareholder assets to pay for their own marketing, distribution, and sales expenses. In a 401(k) context, these fees function as an ongoing commission — often called a “trail” — paid by the mutual fund to whoever sold or maintains the fund in your plan.

12b-1 fees are embedded inside a fund's expense ratio. They are not a separate line item on your statement. They range from 0.25% to 1.00% of assets annually, and they are charged continuously as long as the fund remains in your plan.

On a plan with $2 million in assets, a 0.50% 12b-1 fee generates $10,000 per year in payments flowing from your participants' accounts to a broker or recordkeeper — regardless of whether that party is doing anything to earn it.

The fiduciary problem with 12b-1 fees is structural: the advisor or recordkeeper receiving the trail has a financial incentive to recommend funds that pay it over lower-cost alternatives that don't. Courts have consistently held that plan fiduciaries must understand this compensation arrangement and evaluate whether the total compensation — including 12b-1 payments — is reasonable for the services provided.

What to do: Ask your advisor or recordkeeper for a list of all funds in your plan and whether each pays a 12b-1 fee. Then ask whether any of those funds have a lower-cost share class (institutional or R6 class) available on the platform. If the answer is yes, the reason your plan holds the higher-cost class deserves scrutiny.

Fee #3: High-Cost Share Classes

One of the most common — and most litigated — sources of hidden cost in 401(k) plans is the use of retail mutual fund share classes when lower-cost institutional share classes are available for the same underlying fund.

Consider how this works in practice. A large-cap index fund from a major fund family might be available in four different versions:

• Class A (retail): Expense ratio of 0.65%, including a 0.25% 12b-1 fee
• Class C (retail): Expense ratio of 1.00%, including a 1.00% 12b-1 fee
• Class R3 (retirement): Expense ratio of 0.40%, including a 0.25% 12b-1 fee
• Institutional or R6 class: Expense ratio of 0.07% — no 12b-1 fee

These are not different funds — they hold the exact same underlying securities and produce identical gross returns. The only difference is the cost, and therefore the net return your participants receive. A plan paying 0.65% in expense ratios on a fund available at 0.07% is paying a hidden 0.58% premium — annually, compounded, for every participant dollar invested in that fund.

This issue has been central to some of the largest ERISA fee lawsuits of the past decade, including cases against universities, hospitals, and Fortune 500 companies. The argument is straightforward: if the institutional share class was available and the plan fiduciary failed to select it, participants were harmed.

What to do: Pull the ticker symbol for each fund in your investment menu and look up the full fund family. Ask your recordkeeper or advisor whether an institutional share class exists and, if so, why your plan doesn't use it. The answer should be documented in your fiduciary file.

Fee #4: Revenue Sharing and Sub-Transfer Agent (Sub-TA) Fees

Revenue sharing is the umbrella term for payments that mutual fund companies make to 401(k) service providers — typically recordkeepers — in exchange for having their funds included on the platform. The two most common forms are 12b-1 fees (covered above) and sub-transfer agent (sub-TA) fees.

Sub-TA fees originated from a practical arrangement: recordkeepers took over participant-level accounting from mutual fund transfer agents, and fund companies agreed to pay them for that service. Over time, these payments evolved into a form of “shelf space” compensation — with higher-paying funds gaining more prominent placement or favorable treatment on a recordkeeper's investment menu.

Like 12b-1 fees, sub-TA fees are embedded in a fund's expense ratio. They are not visible as a separate charge, and they can range from 0.10% to 0.50% of assets annually. On a plan with $5 million in assets, 0.25% in sub-TA payments equals $12,500 per year flowing from participant accounts to the recordkeeper — on top of whatever recordkeeping fee the sponsor is paying directly.

The most serious fiduciary risk here is “double-dipping”: a recordkeeper receives both a direct recordkeeping fee from the plan and indirect revenue sharing from the funds. If these are not offset against each other, the recordkeeper is being overpaid at participants' expense.

What to do: Request a written statement from your recordkeeper disclosing all indirect compensation it receives — including sub-TA fees and any other fund-level payments. Then confirm whether those payments offset the direct fee charged to your plan. If the recordkeeper receives both without netting them, the total compensation may be unreasonable and should be benchmarked accordingly.

How to Find These Fees in Your 408(b)(2) Disclosure

Your 408(b)(2) fee disclosure is the primary tool for uncovering all of the above. ERISA requires every covered service provider to disclose both direct compensation (billed to the plan) and indirect compensation (received from third parties, including fund companies). Here's where to look:

• Indirect compensation table: Look for a section specifically labeled “indirect compensation” or “revenue sharing.” This is where 12b-1 fees and sub-TA payments should be disclosed.
• Investment fund schedule: Many 408(b)(2) disclosures include a fund-by-fund table showing the expense ratio, share class, and any revenue sharing rate for each investment option.
• Service fee schedule: Look for an appendix or schedule listing transaction-based fees — loan initiation, distributions, plan amendments, and termination.
• Compensation summary: Some providers voluntarily include a total compensation summary showing direct + indirect compensation combined. If yours doesn't, calculate it yourself.

If your 408(b)(2) does not clearly disclose indirect compensation, that itself may be a compliance failure by the service provider — and you should request a corrected disclosure in writing.

Your Fiduciary Obligation

Understanding these fees is not optional. Under ERISA Section 408(b)(2) and the DOL's fee disclosure regulations, plan fiduciaries are responsible for reviewing all compensation — direct and indirect — paid to every service provider. The standard is not whether you received a disclosure, but whether you understood it and acted on it.

Courts have repeatedly held that plan sponsors cannot discharge their fiduciary duty simply by accepting what a provider tells them. You are expected to:

• Understand the total all-in cost of your plan, including embedded fees
• Benchmark those total costs against comparable plans at least annually
• Document your review process in your fiduciary file
• Take action — renegotiate, replace funds, or change providers — when fees are found to be unreasonable

The good news: you don't need a team of consultants to do this. A structured fee benchmark — comparing your all-in costs to market rates for plans your size — is one of the most defensible pieces of documentation you can add to your fiduciary file.

FEEDUCIARY's benchmarking tool is designed specifically for this purpose. Enter your plan's total fee data, and receive an instant benchmark against current market rates — organized by plan size, and formatted for your fiduciary file.