In a PEO arrangement, your company and the professional employer organization share employer responsibilities for the same workforce: you direct the work, the PEO runs payroll, benefits and HR administration under its own tax accounts. The industry calls this co-employment, and the label carries less legal weight than buyers assume. The IRS states plainly that co-employer is not a term defined in the Internal Revenue Code or its regulations, and that hiring a PEO does not, by itself, move federal employment tax liability off the client. What actually allocates responsibility is the contract, a specific Treasury regulation, and, for certified PEOs, a statute.
What each party does in practice
The working split is consistent across the industry. The client keeps everything that makes the business run: hiring and firing decisions, day-to-day direction, compensation setting and the worksite itself. The PEO takes the administrative employer functions: paying wages under its own employer identification number, depositing and filing employment taxes, administering benefits plans and workers' compensation, and advising on HR compliance. Employees typically see the PEO's name on payslips and benefits cards while reporting to the same managers as before. The attraction is aggregation: a small employer buys payroll discipline and large-group benefits pricing it could not reach alone, for a fee usually set per employee per month or as a share of payroll.
What the IRS actually says about liability
The IRS's guidance on third party payer arrangements is blunt: with a standard, uncertified PEO, the common law employer, the client, generally remains responsible for paying employment taxes and filing returns, even though the PEO is remitting them. A PEO can be designated as the payer under Treasury Regulation 31.3504-2 when it asserts employer status, hires or leases back the workforce and files under its own EIN, but that designation makes the PEO liable alongside the client rather than instead of it. The practical consequence: if an uncertified PEO collects your payroll taxes and fails to remit them, the IRS can still pursue your company for the full amount. Due diligence on a PEO's financial standing is therefore part of the purchase, not paranoia.
How certification changes the answer
Congress created a voluntary certification program, and the IRS certifies PEOs under section 7705(a) after examining financial responsibility, organizational integrity and tax compliance history, with management largely composed of US citizens or residents experienced in employment tax. For a certified PEO, section 3511 does what the co-employment label cannot: the CPEO is treated as the sole employer of worksite employees for federal employment tax purposes, but only for compensation the CPEO actually remits. That is the one structure in which the client genuinely sheds federal employment tax liability on remitted wages. The IRS publishes a list of certified organizations, so verifying a vendor's claimed certification takes minutes and should precede any contract.
What to pin down in the service agreement
Because the statute only settles the certified case, the contract carries the rest. Confirm in writing which party files which returns and under whose EIN; how state unemployment accounts are handled, since state rules on PEO reporting differ from the federal ones; who sponsors the benefits plans and what happens to coverage if the relationship ends; and how the arrangement unwinds, including the return of payroll history and tax records. Ask for evidence of tax deposits on a schedule, not just invoices marked paid. The relationship works well precisely when both sides treat co-employment as a defined table of duties rather than a mood; the agreement and applicable law control the arrangement, and nothing here is legal or tax advice.
Questions people ask about peo co employment relationship
Does co-employment mean the PEO is legally my employees' employer?
Not by default. The IRS notes that co-employer has no definition in federal tax law; a standard PEO administers employment while the client generally remains the common law employer and stays responsible for employment taxes. Only IRS-certified PEOs get sole-employer treatment for federal employment taxes on remitted wages.
Who does the employee actually work for in a PEO arrangement?
Day to day, the client: it directs the work, sets pay and can end the role. The PEO handles the administrative employer functions, so its name appears on payslips and benefits documents. Employment law questions outside tax can read the split differently by state.
What happens if the PEO fails to pay the taxes it collected?
With an uncertified PEO, the IRS can pursue the client for the unpaid amounts, because the common law employer generally remains liable. With a certified PEO, section 3511 places sole federal employment tax liability on the CPEO for compensation it remitted. That difference is the core argument for verifying certification.
Is a PEO the same as an employer of record?
No. A PEO co-administers employees your own entity already employs, mostly a US domestic product. An employer of record is the sole legal employer in a country where you have no entity at all. Several vendors sell both, priced separately; this site's tables show the verified rates.