Moving payroll to a professional employer organization (PEO) doesn’t solve what to do with your 401(k). You still need to decide whether to keep your current plan, move to the PEO’s plan, and understand who handles what.
A PEO retirement plan can reduce some of the admin work, but the details matter.
This guide breaks down plan types, responsibilities, fees, and what happens when you join or leave a PEO. Use our tables and checklists to help you compare your options before signing.
Key Takeaways
- A PEO relationship doesn’t automatically mean joining a multiple employer plan.
- A pooled employer plan is a type of MEP, not another name for every MEP.
- Outsourcing administration doesn’t remove every employer fiduciary duty.
- Compare total fees, investment costs, and employer contributions separately.
- Moving plans, terminating a plan, and distributing savings are different events.
- Get the retirement-plan exit process in writing before joining.
How Does a PEO 401(k) Work?
A PEO 401(k) is a 401(k) arrangement offered or supported through a PEO relationship, rather than a separate legal plan category. The Department of Labor (DOL) explains that a PEO may sponsor a defined-contribution retirement plan. But that doesn’t mean every provider offers the same arrangement.
Depending on the provider, your business might join a PEO-sponsored multiple employer plan, access a pooled employer plan, or keep its own plan with agreed support. Ask which options the provider actually supports.
In practice, eligible employees enroll, payroll deductions fund their accounts, and employer contributions follow the plan’s rules. Different parties then handle tasks like recordkeeping, investments, notices, and plan administration.
Before looking into the package, find out who serves as the plan sponsor, administrator, fiduciaries, and service providers.
Retirement is only one part of an employee benefits package. Evaluate its costs and responsibilities separately from the PEO’s broader benefits administration.
PEO 401(k), MEP, and PEP Terminology
The IRS defines MEPs as plans maintained by two or more unrelated employers. The DOL describes a PEP as a type of MEP. The distinction matters when comparing who runs the plan and what you can control.
| Structure | What it means | What to compare |
|---|---|---|
| Single-employer 401(k) | Your business maintains its own plan. Related employers may count as one employer under applicable tax rules. | Your plan-design choices, provider contracts, administration costs, and retained duties. |
| MEP (other than a PEP) | Unrelated employers participate in a multiple employer plan. A qualifying PEO may sponsor one. | The basis for the arrangement, sponsor identity, employer-level choices, and participation rules. |
| PEP | A specific MEP structure for unrelated employers without a common interest beyond adopting the plan. A pooled plan provider runs it. | The provider’s responsibilities, available plan features, total fees, and employer monitoring duties. |
These distinctions draw on IRS plan definitions, the DOL’s PEO sponsorship rule, and ERISA’s definitions.
A pooled plan provider (PPP) is the PEP’s named fiduciary and plan administrator. Under ERISA’s PPP rules, it’s responsible for required plan administration and must register before operating. The PPP and the PEO aren’t necessarily the same entity.
Pro Tip
Ask two questions: Is it an MEP for tax purposes, and is it one plan under ERISA, the federal benefits law? Tax-code MEP status doesn’t settle the second question. A qualifying PEP is one ERISA plan. Ask the provider to document which rules its plan meets.
What a PEO May Handle
A PEO may coordinate deductions, eligibility data, enrollment support, contribution remittance, participant communications, testing, Form 5500 preparation, and vendors. Some work may instead belong to the recordkeeper, administrator, trustee, or another provider.
The table below shows how these roles can be divided, not how every PEO handles them. Actual responsibilities depend on the plan documents, service agreements, legal requirements, and the work each party performs. The DOL’s fiduciary guide explains why clearly assigning and monitoring these duties matters.
| Role | Typical responsibility to confirm |
|---|---|
| Employer | Supplies accurate employee, payroll, and ownership data; makes permitted employer elections; fulfills retained duties. |
| PEO | Provides agreed payroll feeds, enrollment help, and vendor coordination; may hold additional plan roles. |
| Recordkeeper | Maintains participant account records, processes transactions, and supports statements and account access. |
| Trustee | Holds plan assets under the trust; its authority and investment duties depend on the arrangement. |
| Plan Administrator | Oversees administration, required filings, disclosures, and other administrator duties; may use service providers. |
| Investment Fiduciary | Selects or monitors investments, or manages assets, within its assigned authority. |
One organization may fill several roles. Get a written responsibility map that names who sends the payroll file, moves the money, confirms receipt, and corrects mismatches.
Pro Tip
Ask the provider to demonstrate one payroll cycle, from deduction to participant account. A successful file upload isn’t the same as confirming that the right contribution reached each account.
What Fiduciary Responsibilities Remain
Outsourcing plan tasks doesn’t remove all your fiduciary duties. A fiduciary is a person or entity with authority or responsibility over certain plan decisions, assets, or administration. When acting in that role, they must put the interests of plan participants and beneficiaries first. The DOL explains these duties of care.
Under ERISA’s fiduciary test, fiduciary status depends on what a person controls or does, not just their job title.
In a PEP, each employer keeps the duty to select and monitor the PPP and other named fiduciaries. It also remains responsible for investing and managing the assets tied to its employees and beneficiaries, unless the PPP delegates that role to another fiduciary. More generally, the DOL says hiring service providers is itself a fiduciary function.
If a provider advertises a 3(16) administrator, ask whether the plan names it as administrator and which duties it takes on.
A 3(38) investment manager makes investment decisions for the plan assets it manages. It must qualify as a bank, insurer, or registered investment adviser and acknowledge its fiduciary status in writing.
These statutory roles aren’t interchangeable. Appointing an investment manager doesn’t end the appointing fiduciary’s duty to choose and monitor it carefully.
Build a review process around the duties you keep. Check services, actual fees, provider reports, and unresolved employee complaints. Record why staying with the provider makes sense. The DOL recommends periodic provider monitoring.
Separately, assign someone to check payroll and eligibility data. Clear ownership gives your team a place to escalate errors instead of passing them between vendors.
What Happens to an Existing 401(k) When You Join a PEO?
Don’t end your current 401(k) plan just to match a payroll launch date. Have the existing administrator, receiving provider, and benefits counsel assess these possible paths:
- Keep the existing plan. Confirm the PEO supports its payroll connection and what administration remains separate.
- Merge or transfer into the new arrangement. Confirm acceptance of assets and liabilities, records, and required participant protections.
- Before merging or transferring an existing plan, ask your administrator whether IRS Form 5310-A is required. Some transactions require notice at least 30 days in advance, while others are exempt.
- Terminate the existing plan, if legally permitted. Check distribution restrictions, vesting, notices, filings, and any successor plan before taking action.
The IRS distinguishes these kinds of plan transition outcomes. The right route for your business depends on its documents and facts, but joining a PEO isn’t itself a corporate merger.
Protect balances and avoid payroll gaps
A merger can’t reduce protected benefits. Full or partial plan termination generally requires full vesting for affected participants. That means they own their full account balance, including employer contributions. Have counsel check which protections apply.
Before switching, verify eligibility, service history, contribution elections, year-to-date deferrals, employer contributions, and loan repayments. Confirm the last deduction under the old process and the first under the new one.
A move may involve a blackout that restricts investment changes, loans, or distributions for more than three straight business days. For a covered blackout, notice rules generally require written notice to affected participants and beneficiaries 30–60 days before the last date they can exercise those rights. Exceptions apply. Ask the administrator to set the notice and transition dates.
Pro Tip
Don’t promise employees a payout or rollover just because the old plan is ending. Under IRS distribution rules, a successor defined-contribution plan can prevent termination-based distributions.
Compare Fees and Investments
A pooled structure isn’t automatically cheaper. The DOL advises comparing total costs and services, including direct and indirect provider compensation. The standard is reasonable fees for the services, not just the lowest quote.
Use a total-fee worksheet, not the headline price
Give your current provider and the PEO the same assumptions for participants, assets, payroll frequency, expected transactions, and service scope. Then fill out this worksheet using their written disclosures. The categories follow the DOL’s 401(k) fee comparison tool.
For each blank, enter an annual dollar estimate and who pays: employer, plan, or individual participant. Separate any charge already included in another row.
Enter annual amounts in USD after any fee credits. Leave unknown costs blank; enter 0 for confirmed no-cost items.
Use nonnegative dollar amounts with up to two decimal places.
Loading calculator v15…
Use matching assumptions and count each fee once. For a pooled plan, enter your company’s share only. Entries are not saved automatically. Estimates only; verify costs with the providers.
Ask about revenue sharing (payments from investments to service providers) and any fee credits. Don't add a payment again if it's already included in a fund expense or another charge.
For example, a separate 0.25% annual service fee on $2 million in assets would cost $5,000 a year. That excludes other fees and is only an example, not an estimate of typical market pricing.
For your business budget, add employer-paid fees, employer contributions, and applicable one-time costs. Separately show costs deducted from employee accounts. Employee salary deferrals aren't provider fees or employer-funded contributions.
Pro Tip
Request both the first-year total and the ongoing annual total. Then price an exit. A low recurring quote doesn't tell you the cost of conversion, transfer, or ending the service agreement.
Compare what employees receive for the fees
Request the latest investment comparison disclosures and review the investment lineup, share classes, target-date funds, restrictions, and any managed-account or advice fees. Also ask who chooses and monitors the investments and how employees are notified about changes.
Then compare the employee experience. Look at enrollment support, mobile access, phone help, language options, and assistance with loans or distributions. Ask for a demo based on common employee questions, not just the admin dashboard. A lower employer cost matters less if more of the expense is just passed on to participants.
PEO 401(k) Compliance and Reporting
At a high level, ERISA governs plan protections and fiduciary standards, and the Internal Revenue Code governs tax qualification. The DOL's plan oversight guide explains the agencies' roles. Ask who is responsible for each area below.
Form 5500 and audits
A single-employer plan usually files its own Form 5500. If the arrangement is recognized as one ERISA MEP, including a PEP, it generally files one plan-level Form 5500 instead of separate forms for every participating employer. Check the Form 5500 instructions to confirm Schedule MEP requirements and what information your company must provide.
Larger plans generally need an independent audit. For defined-contribution plans, size is generally based on the number of participants with account balances, with 100 participants marking the usual dividing line between small and large plans. First-year counting rules and the 80–120-participant rule can also change the result.
Your company's headcount alone doesn't determine whether a MEP or PEP needs an audit. Ask for the plan-level assessment and find out what share of the audit costs your company would pay.
Testing
Traditional 401(k)s generally face annual nondiscrimination tests, which check whether contributions disproportionately favor highly paid employees. Some designs avoid specified tests if their conditions are met. Confirm employer-level testing, required ownership and compensation data, and responsibility for corrections.
Deposits, documents, and disclosures
Employee contributions need to be deposited into the plan on time under applicable timely deposit rules. Ask who’s responsible for keeping plan documents updated and sending employees the summary plan description, fee disclosures, and other required notices.
You should also confirm how current automatic-enrollment rules apply to your company. Ask whether any exceptions under IRS guidance apply to your participation.
Conflicts and corrections
Prohibited-transaction rules limit self-dealing and certain transactions involving related parties. Ask how the provider reviews potential conflicts, late contributions, and failed compliance tests.
If something does go wrong, different correction programs may apply. IRS plan correction procedures and the DOL’s fiduciary correction program cover different issues and have different requirements. A PEO contract can assign responsibilities, but it doesn’t guarantee compliance.
Questions to Ask a PEO About Its Retirement Plan
Use this retirement-plan due-diligence checklist when you choose a PEO. Request documents and named owners, not just yes-or-no answers.
- Structure: What's the exact plan type, sponsor, and legal plan name? Is it one ERISA plan? For a PEP, request the PPP's Form PR registration details.
- Fiduciaries: Who are the named fiduciaries? What 3(16) or 3(38) roles are claimed, acknowledged in writing, and actually delegated? What remains with us?
- Providers: Who are the recordkeeper, trustee, administrator, and investment fiduciary? Which services are subcontracted?
- Eligibility and contributions: What are the entry dates, service requirements, automatic-enrollment terms, match formula, and vesting rules? Which choices can we change?
- Investments and support: Can we review the full lineup, share classes, target-date funds, advice options, and participant support standards?
- Total cost: Who pays every service, investment, transaction, audit, and exit charge? What's bundled, credited, or subject to increase?
- Testing and reporting: Who performs testing, files Form 5500, determines audit treatment, and pays for corrections?
- Data integration: Which payroll and employee fields transfer? Who checks deductions against deposits and participant accounts?
- Joining: What happens to our current plan, balances, loans, service records, notices, and payroll deductions?
- Leaving: What notice, successor-plan decisions, transfer approvals, fees, records, and provider timelines apply?
Pro Tip
Keep the plan documents, participation agreement, service contract, fee disclosures, fiduciary acknowledgments, and transition terms in one place. If you get conflicting answers, have benefits counsel clear them up before you sign.
What Happens to the 401(k) When You Leave the PEO?
Treat the retirement-plan exit as its own project. Ending the PEO service agreement doesn't, by itself, establish a right to withdraw retirement savings, as distribution rules still apply.
Start planning before you give notice. Ask whether you can retain a separate plan, establish a successor plan, transfer or merge assets, or leave existing balances where they are. Get the permitted path and each provider's timeline in writing.
Build the retirement transition around four controls:
- Secure the receiving arrangement. Confirm acceptance of assets, records, and loans where permitted. IRS guidance explains that loan terms matter, so don't promise automatic loan transfers.
- Keep deductions continuous. Test the new payroll connection and reconcile final and opening contributions, repayments, and year-to-date totals.
- Tell employees what changes. Assign required notices, blackout communications, account-access instructions, and a contact for questions.
- Close the records loop. Confirm transferred balances, fees, unresolved corrections, and responsibility for reporting covering the exit period.
The Bottom Line on PEO Retirement Plans and MEPs
When it comes down to deciding on a PEO 401(k), choose the retirement plan you can clearly explain, manage, and monitor.
Compare the PEO option with maintaining your own plan based on structure, responsibilities, total costs, employee support, and what happens if you leave.
Use the worksheet and checklist to get key answers in writing, then have qualified benefits counsel review the documents before you commit.
This guide provides general information, not legal, tax, or investment advice. Plan-specific decisions require review of the governing documents and applicable law.
