Key Takeaways
- 401k fees hide in three places: fund expense ratios, administrative fees, and revenue-sharing arrangements.
- A 1% annual fee difference cuts a 30-year ending balance by roughly 28%.
- You can see your plan's fees in the annual disclosure your plan must send you.
Where 401k Fees Hide
Most investors only notice the expense ratio on their funds, but a 401k typically carries three layers of cost. The fund expense ratio is the annual percentage the fund company takes from assets — an S&P 500 index fund might charge 0.03% while an actively managed fund charges 0.60% to 1.00% or more. The plan administrative fee covers recordkeeping, compliance testing, and customer service; it may be charged per participant, as a flat dollar amount, or as a percentage of assets. Finally, revenue sharing quietly funnels a slice of the fund expense ratio back to the plan provider — which is why two plans offering the "same" fund can have different total costs. Your plan must send an annual fee disclosure (under ERISA Section 404a-5) listing all of these; if you cannot find it, the HR portal or plan website usually has it.
The 1% Math
Fees compound against you. Consider $50,000 growing at 7% gross over 30 years: at a 0.5% total cost the ending balance is roughly $285,000, but at 1.5% it falls to about $220,000 — a gap of roughly $65,000, or 23% of the balance, for just one percentage point of extra fees. Over a full career the drag is worse, because contributions made early have decades to compound. Plan sponsors negotiate institutional share classes that individual investors cannot buy, which is why a good 401k can actually beat a retail IRA on cost — but a poorly managed plan with high administrative fees and expensive funds can cost you more than any tax advantage provides.
How to Audit Your Plan's Fees
- Read the annual 404a-5 fee disclosure and note the total plan cost (often shown as a per-$1,000 figure).
- List the expense ratios of the funds you own; compare each to the lowest-cost index alternative in the plan.
- Check whether the plan charges per-participant fees and how they are deducted.
- If you are leaving the job, compare the old plan's total cost against a low-cost IRA — that comparison often decides the rollover question.
What to Watch Out For
- Target-date funds are convenient but charge 0.30%-0.60% on average; check whether the plan's target date series is the institutional version.
- Beware of funds with 12b-1 fees or loads in older plans — both are pure drag with no benefit to you.
- Annuity or insurance products inside a plan can carry surrender charges and mortality-and-expense fees that are easy to miss.
- If fees are high and you are leaving anyway, a rollover to an IRA is often the single best fee-reduction move available.
Fee Comparison: 401k vs IRA
The rollover decision often comes down to this table. A typical large-plan 401k offers institutional index funds at 0.03%-0.10% expense ratios plus a recordkeeping fee of 0.10%-0.30% of assets — an all-in cost near 0.2%-0.4%. A small-business 401k with a limited menu can run 1.0%-1.5% all-in when administrative fees are spread over few participants. An IRA at a low-cost brokerage costs 0.03%-0.10% for index ETFs with zero account fees. The crossover point: if your plan's all-in cost exceeds what you would pay in an IRA by more than about 0.3 percentage points, rolling over saves real money — on a $100,000 balance, every 0.1% is $100 per year, and over 30 years a 0.5% annual saving compounds to roughly $40,000. If your plan is genuinely cheap, staying put is fine. The mistake is assuming your plan is cheap without checking the 404a-5 disclosure.
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Use the Calculator →Fee Disclosure: Where to Look
The law requires your plan to send a 404a-5 participant fee disclosure at least once a year. It shows the plan's administrative expenses, each fund's expense ratio, and any transaction fees. The easiest comparison: take your balance, multiply by 1%, and that is what a 1% fee costs you annually — on $100,000 that is $1,000 a year, or roughly $2,300 in lost growth per year at a 7% return. The 408(b)(2) disclosure covers the plan's own service provider costs, which is where hidden revenue-sharing fees hide. If your plan's all-in cost is above 0.75%, an IRA rollover at a low-cost brokerage usually cuts it to under 0.10%. One fee that surprises people: plan termination or rollover fees of $50-$150 charged when you leave — small in isolation, but worth asking about before initiating the transfer.