A multiple employer plan is a single retirement plan, almost always a 401(k), that two or more unrelated businesses share under one plan document and one trust. Instead of each company running its own plan, the group operates under a common framework administered by a central sponsor, which lowers investment fees, consolidates compliance work, and shifts most of the fiduciary burden away from the individual employer. The structure has existed for decades, but the 2019 SECURE Act and its 2022 follow-up rewrote the rules in ways that make it far more accessible to small businesses than it used to be.
How the Plan Actually Works
Every participating employer adopts the same plan document. That document sets eligibility, vesting, contribution rules, and distribution options for everyone in the plan. Assets from all the employers sit together in a shared trust, which gives the plan meaningful negotiating leverage with fund managers and recordkeepers. A small bakery on its own has almost none; a plan with a few hundred employers behind it can access institutional share classes and lower per-participant fees.
The consolidation extends to paperwork. The plan files one Form 5500 annual return covering every employer, undergoes one independent audit if it crosses the 100-participant threshold, and runs one round of nondiscrimination testing. A standalone 401(k) audit routinely runs upward of $10,000 a year, and for a business with fewer than 50 employees, avoiding that cost is often what makes offering a plan feasible at all.
A central plan sponsor or pooled plan provider does the day-to-day work: picking and monitoring investments, coordinating with the recordkeeper, running compliance tests, and filing with the IRS and Department of Labor. For an owner without in-house HR or compliance staff, that shift is the point of joining.
The Three Types You’ll Encounter
Closed MEPs
A closed MEP is limited to members of a specific trade association, professional group, or industry organization. The sponsoring association has to be genuine, with a real purpose and activities beyond running a retirement plan. The Department of Labor calls this the “bona fide group” standard. A state veterinary association offering a plan to member clinics fits the model. The trade-off is exclusivity: if your business doesn’t belong to a qualifying group, you can’t join.
PEO-Based MEPs
Professional employer organizations have offered MEPs to their client companies for years. The PEO acts as a co-employer for payroll and benefits, which gives it the legal footing to sponsor a plan for its clients. If you already use a PEO for payroll, adding retirement benefits through its plan is straightforward. The catch is that the plan is tied to the PEO relationship. Leave the PEO, leave the plan.
Pooled Employer Plans
The SECURE Act created pooled employer plans, or PEPs, effective in 2021, and they’re the reason most small businesses now have a realistic path into a MEP.1U.S. Department of Labor. Setting Every Community Up for Retirement Enhancement Act of 2019 (SECURE Act) A PEP lets completely unrelated businesses join the same 401(k) with no shared industry, no association tie, and no geographic link. A bakery, a software company, and a plumbing contractor can all participate in one plan.
A PEP is run by a pooled plan provider, defined under ERISA Section 3(44) as the entity that serves as the plan’s named fiduciary and plan administrator and handles the administrative duties needed to keep the plan compliant.2Federal Register. Registration Requirements for Pooled Plan Providers The PPP must register with the Department of Labor on Form PR through the EFAST2 electronic filing system before it can operate.3U.S. Department of Labor. Form PR and Instructions Registration for Pooled Plan Provider Before signing a joinder agreement, verify the provider’s registration, review the fee disclosures they’re required to give you, and check that the investment menu fits your workforce.
Not to Be Confused With a Multiemployer Plan
These two terms trip up almost everyone. A multiemployer plan is a collectively bargained arrangement between unions and multiple employers, governed by a joint labor-management board of trustees and subject to withdrawal liability enforced by the Pension Benefit Guaranty Corporation.4Pension Benefit Guaranty Corporation. Multiemployer Plan Election Procedures Under the Pension Protection Act Think of the building trades or Teamsters plans. A multiple employer plan has no union involvement, no bargaining requirement, and no PBGC withdrawal liability for defined contribution plans. If your business is non-union and you’re looking at pooling with other employers to offer a 401(k), the multiple employer plan is the structure you want.
What You Still Have to Do as an Employer
The main selling point of a MEP is the fiduciary load it takes off your desk. The PPP or plan sponsor is the named fiduciary and plan administrator, handling investment selection, compliance testing, and vendor management. But participating employers don’t walk away from everything.
Under ERISA, each employer keeps the fiduciary duty to select and monitor the PPP or plan sponsor, and to monitor any other named fiduciary designated under the plan.3U.S. Department of Labor. Form PR and Instructions Registration for Pooled Plan Provider In practice, that means periodically checking whether the provider is doing its job, keeping fees reasonable, and performing competently. Lighter than running your own plan, but not nothing.
Employers also remain responsible for remitting employee contributions on time. Withholding money from a paycheck and sitting on it is a prohibited transaction under ERISA no matter who administers the plan. The Department of Labor treats participant contributions as plan assets as soon as they can reasonably be segregated from the employer’s general accounts, and delays can trigger civil liability and potential criminal exposure.5U.S. Department of Labor. Field Assistance Bulletin No. 2008-01
The One Bad Apple Problem Is Fixed
For years the biggest reason to hesitate on a MEP was the “unified plan” rule. If one participating employer failed nondiscrimination testing or made an impermissible contribution, the IRS could strip the tax-qualified status from the entire plan and every employer in it. One bad apple, everyone loses.
The SECURE Act ended that risk by adding Section 413(e) to the Internal Revenue Code. Under this provision, the plan won’t lose its qualified status just because one employer fails to hold up its end. The plan document must require that a noncompliant employer’s share of assets be spun off into a separate plan or rolled into individual retirement accounts, and that employer alone bears the liability.6Office of the Law Revision Counsel. 26 USC 413 – Collectively Bargained Plans, Etc. Everyone else keeps their tax benefits. This one change did more to accelerate PEP adoption than any other piece of the law.
Contribution Limits, Auto-Enrollment, and Part-Time Workers
A MEP or PEP follows the same IRS contribution limits as any other 401(k). For 2026, the elective deferral limit is $24,500, up from $23,500 in 2025. Workers age 50 and older can add $8,000 in catch-up contributions, for a total of $32,500. SECURE 2.0 also created a higher catch-up tier for participants ages 60 through 63, who can defer an extra $11,250 instead of $8,000, for a total of $35,750.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
The limit is per person across all employers in the plan. An employee working for two participating employers in the same MEP can’t double up. Nondiscrimination testing is run under IRC Section 413(c) as if all employees of every participating employer worked for a single company.6Office of the Law Revision Counsel. 26 USC 413 – Collectively Bargained Plans, Etc.
SECURE 2.0 requires most new 401(k) plans established after December 29, 2022, including new PEPs, to enroll eligible employees automatically. Under IRC Section 414A, the default deferral rate has to be at least 3% and no more than 10%, and it must escalate by one percentage point a year until it reaches at least 10%. Employees can always opt out or change the rate. Plans that existed before the effective date are grandfathered.
SECURE 2.0 also opened the plan to long-term part-time workers. For plan years after December 31, 2024, any employee who logs at least 500 hours in each of two consecutive 12-month periods must be allowed to make elective deferrals. The original SECURE Act required three consecutive years; SECURE 2.0 shortened it to two.8Internal Revenue Service. Additional Guidance With Respect to Long-Term, Part-Time Employees For MEPs and PEPs with employers in retail, hospitality, or home health, this significantly broadens who has to be offered the plan.
Filings and Audits at the Plan Level
The plan files a single Form 5500 covering all participating employers instead of one for each. For calendar-year plans, the deadline is July 31, extendable by two and a half months to October 15 if the plan files Form 5558 in time.9Internal Revenue Service. Form 5500 Corner The plan sponsor or PPP handles this filing, so individual employers don’t carry the direct filing obligation.
An independent audit is required if the combined participant count across all employers exceeds 100 at the start of the prior plan year. That’s a plan-level count. Even if your business has 12 employees, the plan as a whole may well be over the threshold. The difference is that everyone shares the cost of one audit rather than paying for their own.
Leaving the Plan
Withdrawing from a MEP is governed by the plan document and, for PEPs, by the framework in IRC Section 413(e). The document typically spells out a notice period and the mechanics for spinning off the departing employer’s share of assets and liabilities. Under 413(e), the departing employer’s portion transfers to a new plan maintained by that employer alone, to individual retirement accounts for affected participants, or to another arrangement the IRS considers appropriate.6Office of the Law Revision Counsel. 26 USC 413 – Collectively Bargained Plans, Etc.
Unlike a multiemployer plan, there’s no PBGC-assessed withdrawal liability for defined contribution MEPs. Your obligation on the way out is making sure your employees’ accounts are properly transferred and any outstanding contributions are paid. Read the withdrawal provisions in the plan document before you sign the joinder agreement. Some plans include short lockup periods or transition fees, and it’s easier to see those going in than to discover them when you want to leave.