Co-employment is a contractual arrangement in which a business and a professional employer organization (PEO) share employer responsibilities for the same group of workers. The business keeps control over what employees do each day. The PEO takes over payroll, tax filings, benefits, and other back-office human resources work. Both entities are legally employers of the same people at the same time, which is what makes the arrangement useful and what creates the legal exposure you need to understand before signing on.
Who Does What in a Co-Employment Arrangement
Three parties are involved: the client company (also called the worksite employer), the PEO (the administrative employer), and the employees themselves. The client directs the work, sets production goals, and runs daily operations. The PEO processes payroll, files employment tax returns, administers health insurance, and maintains employment records. Employees answer to the client on the job and receive their paychecks and benefits paperwork through the PEO.
The client service agreement is where the split gets nailed down. The worksite employer usually keeps authority over hiring, work assignments, performance reviews, and termination. The PEO handles payroll processing, benefits procurement, regulatory filings, and often the employee handbook. When something goes wrong, that contract language is a starting point for allocating liability, though as you’ll see below, it doesn’t have the last word.
Read the termination clause before you sign anything. Industry-standard agreements often require 90 days’ written notice to end the relationship at the close of a contract year, with shorter notice (roughly 30 days) if the PEO stops providing services. Either party can usually terminate immediately for a material breach. Pay attention to what happens to employee benefits and payroll during any transition window, because gaps create compliance exposure.
Payroll Taxes and the Certified PEO Distinction
The PEO takes on the payroll tax workload. It withholds and remits the employee’s share of Social Security (6.2 percent) and Medicare (1.45 percent) and pays the matching employer portions. Social Security tax applies to wages up to $184,500 in 2026. The PEO also handles Federal Unemployment Tax Act (FUTA) obligations, which generally come out to a net rate of 0.6 percent on the first $7,000 of each employee’s wages after the standard 5.4 percent credit.
Reporting is centralized under the PEO’s own Federal Employer Identification Number. The PEO files aggregate employment tax returns and attaches a Schedule R that allocates the amounts back to each client. W-2s at year end typically show the PEO as employer of record. State unemployment tax works the same way, with the PEO filing quarterly and paying premiums based on its assigned experience ratings.
Not all PEOs carry the same tax weight. The IRS runs a voluntary certification program under 26 U.S.C. § 3511. A certified PEO (CPEO) is treated as the sole employer for federal employment tax purposes on the wages it pays. Two practical consequences follow.
First, when a CPEO pays wages on behalf of a client, the client is generally not liable for those federal employment taxes. With a non-certified PEO, the client remains on the hook if the PEO fails to remit. Second, a CPEO gets successor employer treatment, which keeps the wage base from resetting when a company joins or leaves mid-year. Without that protection, a mid-year switch to a non-certified PEO gets no credit for wages already paid, and employees and the employer can end up overpaying Social Security and FUTA until the duplicates are sorted out at filing time.
PEO administrative fees typically run between 2 and 12 percent of total gross payroll, depending on workforce size, the services included, and industry complexity.
Workers’ Compensation and Workplace Safety
In most co-employment arrangements, the PEO provides workers’ compensation coverage. Some PEOs use a master policy covering all clients under a single experience modification rate; others use a multiple coordinated policy model, giving each client an individual policy with its own claims history driving the rate. The master approach can help smaller companies with limited claims history. The individual policy model rewards clients with strong safety records.
OSHA responsibility is shared. The client controls the physical worksite and directs how work is performed, so it bears primary responsibility for safe conditions and generally maintains the OSHA 300 log at its location. But OSHA can cite multiple employers for hazards on the same worksite, and a PEO that ignores known hazards at a client site isn’t shielded because it doesn’t control the workspace.
Workers’ compensation is the exclusive remedy for on-the-job injuries in every state, so a covered employee generally cannot sue either co-employer in tort for a workplace injury. That protection depends on coverage actually being in place. If the PEO lets coverage lapse or never secures it, both entities lose tort immunity and face direct lawsuits from injured workers.
Employee Benefits, Retirement, and the ACA
Access to better benefits is often the main reason a company enters a co-employment arrangement. Because a PEO pools employees across many clients, it can negotiate group health, dental, vision, and other benefits at a scale a 20-person company cannot reach on its own. The PEO usually administers enrollment, fields claims questions, and handles COBRA notices when employees leave.
Retirement Plans Under ERISA
Many PEOs sponsor multiple employer plans (MEPs) that let client company employees participate in a 401(k) or similar plan. Under ERISA, the PEO acting as plan sponsor generally takes on fiduciary responsibilities: selecting and monitoring investments, keeping fees reasonable, and staying compliant with IRS and Department of Labor requirements. The PEO typically serves as plan administrator for reporting and disclosure.
Client companies still have real exposure. If a PEO picks an underperforming or expensive plan and fails to monitor it, the fiduciary breach harms the client’s own employees. Before signing on, ask to see the PEO’s investment policy statement, fee disclosures, and records of regular plan committee meetings.
ACA Employer Mandate
The Affordable Care Act’s employer shared responsibility rules apply to applicable large employers (ALEs), meaning employers with 50 or more full-time or full-time-equivalent employees in the prior year. In a co-employment arrangement, the client company determines its own ALE status based on its own workforce. If the client is an ALE, the PEO must help meet the obligation to offer affordable, minimum-value coverage to at least 95 percent of full-time employees. Falling short exposes both parties to IRS penalty assessments.
When Are the Two Employers “Joint Employers”?
A contract label doesn’t decide whether two organizations are joint employers. Courts and agencies apply fact-specific tests, and the standard shifts depending on which law is at issue. A relationship that qualifies as joint employment under one federal statute might not under another.
FLSA
The Department of Labor has not had a formal FLSA joint employment regulation since rescinding its prior rule in July 2021. In practice, the DOL and courts have applied a vertical joint employment analysis that varies by federal circuit. A 2026 proposed rulemaking would set a four-factor balancing test: whether the potential joint employer hires or fires, supervises and controls work schedules or conditions, determines the rate and method of payment, and maintains employment records. No single factor would be dispositive.
NLRA
Under the National Labor Relations Act, the standard reverted to the NLRB’s 2020 rule after a federal court in Texas vacated the Board’s 2023 joint employer rule in March 2024. The 2020 rule requires an entity to exercise “substantial direct and immediate control” over at least one essential term of employment (wages, benefits, hours, hiring, discharge, or supervision) before it can be deemed a joint employer. Reserving the contractual right to control workers, without actually exercising it, is not enough.
Title VII and Other Discrimination Laws
Courts applying Title VII generally use common-law agency factors, looking at who controlled hiring and firing, set pay, supervised daily work, maintained employment records, and handled discipline. A PEO that processes payroll but exercises no real authority over workplace conditions is less likely to be treated as a joint employer under these laws than one that actively participates in personnel decisions.
Shared Federal Labor Law Liability
Once joint employer status attaches, both organizations share obligations. Four areas do most of the practical damage.
Fair Labor Standards Act
Both co-employers are jointly and severally liable for minimum wage and overtime compliance. If an employee works more than 40 hours in a week and doesn’t receive time-and-a-half, either or both entities can be held responsible for back wages and liquidated damages. Hours worked for both employers in the same workweek get combined for overtime purposes.
Family and Medical Leave Act
Jointly employed workers must be counted by both employers when determining FMLA coverage and eligibility. A client with only 30 employees of its own can push a PEO past the 50-employee threshold once those employees are added to the PEO’s rolls, and the reverse works the same way. Eligibility also requires that at least 50 employees work within 75 miles of the employee’s worksite, measured by surface transportation routes.
Eligible employees can take up to 12 weeks of unpaid, job-protected leave for qualifying medical and family reasons. The primary employer (usually the client in a PEO arrangement) has to provide the leave and maintain health benefits during it. Both entities face liability for violations.
Americans With Disabilities Act
Both co-employers must engage in the interactive process when an employee requests a reasonable accommodation. A contract assigning ADA responsibilities to one party doesn’t shield the other from liability for disability discrimination. The client, which controls the workspace and job duties, is usually better positioned to implement accommodations like modified schedules or ergonomic equipment. The PEO cannot disclaim responsibility by pointing to the contract.
Title VII
Both organizations must keep the workplace free of discrimination and harassment based on race, religion, sex, national origin, and other protected characteristics. A PEO that receives harassment complaints from a client’s worksite and does nothing faces direct liability. Both parties need functioning complaint procedures, trained investigators, and follow-through.
State Licensing Requirements
PEOs are required to register or obtain a license in roughly 35 states. Requirements vary, but they often include posting a surety bond, providing proof of workers’ compensation coverage, and submitting audited financial statements. Some states require annual renewals and ongoing financial reporting. Before signing on, verify that the PEO is properly licensed in every state where you have employees. An unlicensed PEO operating in a state that requires registration can leave the co-employment relationship legally unrecognized there, leaving you solely responsible for obligations you thought were shared.
Ending the Arrangement
Leaving a PEO triggers a cascade of administrative and legal steps. You need to stand up your own payroll system or hire a new provider, secure independent workers’ compensation and health insurance, and transfer all employee records. Any gap in health coverage can trigger ACA penalties. A lapse in workers’ compensation exposes you to uninsured injury claims.
Timing matters. Leaving mid-year with a non-certified PEO means the new payroll provider gets no credit for wages already paid, potentially resetting FICA and FUTA wage bases and causing employees to overpay Social Security until they claim a refund at tax time. Exiting at year-end avoids this and lines up with benefit enrollment cycles. Companies using a CPEO have more flexibility, because the successor employer rules under 26 U.S.C. § 3511 keep the wage base from resetting.
Retirement plan transitions are tricky. If employees are in the PEO’s multiple employer 401(k), you’ll need to either establish your own plan and facilitate rollovers or make sure employees understand their distribution and rollover options. COBRA obligations for recently terminated employees may need to transfer as well. Build at least 90 days of lead time into any exit plan, and confirm in writing which entity remains responsible for tax filings and benefit administration during the transition.