HR outsourcing through a PEO is a specific legal arrangement, not a general services contract. The PEO becomes a co-employer of your workforce: it files payroll taxes under its own employer identification number, sponsors benefit plans, and takes on defined compliance tasks, while your company keeps control of who is hired, what they work on and how they are managed. That structure is what separates a PEO from ordinary outsourced HR administration, and it is why the decision deserves more diligence than picking a software vendor. This page covers what transfers, what stays, and how the PEO model compares with the alternatives.
What the PEO takes over
The core bundle is payroll, benefits, compliance assistance and other HR services, delivered under co-employment. In practice that means the PEO calculates and files employment taxes under its own EIN, sponsors and administers health insurance and workers' compensation plans it can price across its whole client base, handles unemployment insurance administration, and supplies HR expertise your company would otherwise have to hire. NAPEO reports that about 200,000 mostly small and mid-size businesses use PEOs, and that 14% of employers with 20 to 499 employees do so; the pooling across that base is the economic engine, because it buys benefit plans at a scale a 30-person company cannot reach alone.
What stays with you
Co-employment splits the employment relationship; it does not hand it over. Your company continues to decide whom to hire and dismiss, sets compensation, directs the daily work and owns the culture. You also keep real compliance exposure: the PEO's role in tax filing and benefits does not make workplace safety, discrimination law or wage-and-hour decisions someone else's problem, because those flow from how you actually run the workplace. Treat the PEO's compliance assistance as exactly that, assistance. The client service agreement defines precisely which obligations sit where, and it, not the sales material, controls; read it before signing and keep nothing on this page as legal advice.
Certification is the diligence shortcut
Because the PEO files your payroll taxes under its own EIN, its financial soundness is your problem: money you hand over for taxes has to actually reach the government. The IRS certification program created by the Tax Increase Prevention Act of 2014 under Internal Revenue Code section 7705 exists for exactly this reason. A Certified Professional Employer Organization must maintain a US location, demonstrate financial responsibility, organizational integrity and federal, state and local tax compliance, and be run by people with employment tax knowledge. Checking a candidate vendor against the IRS's published CPEO list is the single fastest piece of diligence available in this market.
PEO against the other outsourcing models
If you want administrative help without co-employment, an ASO delivers payroll and HR administration while your company remains the sole employer of record, filing under its own EIN, typically for a per-employee monthly fee in the $50 to $250 range. If you want to employ people in a country where you have no entity, neither model works; that is the employer of record product, where the vendor is the sole legal employer abroad. PEOs generally price as a percentage of payroll, commonly 2% to 15%, or a flat per-employee fee, and suit employers of roughly five to a hundred people without a dedicated HR function. The verified pricing table on this site covers vendors across these product lines.
Questions people ask about hr outsourcing peo
Is using a PEO the same as outsourcing my HR department?
Not quite. A PEO takes over payroll, benefits sponsorship and defined compliance administration under co-employment, but hiring decisions, management and workplace practice stay with you. It replaces HR administration, not HR judgement.
Do my employees stop being my employees?
No. Co-employment means the PEO becomes the employer of record for administrative purposes, such as payroll taxes and benefit sponsorship, while your company remains their employer for direction, dismissal and daily work.
How does a PEO differ from an ASO for HR outsourcing?
An ASO administers payroll and HR tasks while your company stays the sole employer and files taxes under its own EIN. A PEO co-employs, files under its own EIN and sponsors the benefit plans. The ASO keeps more control with you; the PEO moves more administration off you.
What should I verify before signing with a PEO?
Whether it holds IRS CPEO certification, how the fee is calculated and what it excludes, which benefit plans it sponsors and what happens to them if you exit, and what the client service agreement says about termination notice and data return.