They both deal with employees and they both involve a third party, but a PEO and a staffing agency solve fundamentally different business problems. Mixing them up costs companies real money. Here's the clean version, written by an independent PEO broker.
| Dimension | PEO (Professional Employer Organization) | Staffing Agency |
|---|---|---|
| Who hired the workers? | You did. They are your employees in substance and direction. | The agency did. They are the agency's employees, placed at your work site. |
| Who issues the W-2? | The PEO (as administrative employer of record). | The staffing agency. |
| Who directs day-to-day work? | You do — same as if no PEO existed. | You direct the assignment; the agency may retain HR oversight. |
| Typical duration | Multi-year, ongoing relationship. | Temporary or project-based; some agencies do "right to hire." |
| Workers comp coverage | PEO's master policy covers your employees. | Agency's policy covers agency workers. |
| Benefits eligibility | Employees access PEO's master benefit plans (health, dental, 401(k), etc.). | Agency may or may not offer benefits to its placed workers. |
| Federal tax liability | CPEO: solely on PEO. Non-CPEO: joint and several with employer. | Solely on agency. |
| Typical pricing | PEPM ($59–$300+) or % of payroll (2–4%). | Markup on hourly bill rate (typically 30–80%). |
| Hiring authority | You. PEO doesn't recruit; it administrates. | Agency. They source, vet, and place candidates. |
| Termination authority | You decide; PEO advises on compliance. | You can end the assignment; agency handles agency-employee termination. |
The most important distinction is structural. A PEO operates under co-employment — a legal arrangement codified in IRS Notice 99-6 and subsequent IRC sections that allows the PEO to share certain employer responsibilities with your business. Your employees remain your employees in every substantive way: you recruit, hire, manage, train, promote, and terminate them. The PEO handles the administrative employer functions: payroll processing, tax remittance, benefits administration, workers comp coverage, and HR compliance.
A staffing agency operates under a supplied-labor model. The agency recruits and hires workers as its own employees, then places them at client work sites under a service agreement. The client pays the agency a bill rate that includes the worker's wages plus an agency markup. The worker has no direct employment relationship with the client; the agency is the sole employer.
These two structures lead to different IRS treatment, different state employment law treatment, different unemployment insurance treatment, different workers comp treatment, and different liability allocation in lawsuits. They're not interchangeable — and confusing them in your finance or HR conversations creates real costs.
You have full-time employees you've hired or plan to hire directly, and you want to outsource the HR/payroll/benefits/compliance administration. Typical examples:
In every case, the workers are your employees. You direct their work. The PEO is your HR back-office.
You need workers but don't want to (or can't yet) hire them directly. Typical examples:
In every case, the workers are the agency's employees. You're paying for their work, not for the employment relationship.
Many of our clients run both arrangements concurrently — full-time team on a PEO, seasonal/project workers from staffing agencies. The two coexist cleanly because they apply to different workers. The only thing to watch is the agency-worker tax treatment, which interacts with your PEO's records (the PEO doesn't issue tax forms for agency workers, but your AP department records the bill rate as a service expense rather than as wages).
No. "Employee leasing" is a legacy term for the PEO co-employment model from the 1980s–90s, before NAPEO standardized "Professional Employer Organization." Some states (notably Florida and Texas) still use "employee leasing" in their licensing statutes. It's the same thing as a PEO — co-employment of your existing workforce. Staffing agencies are a different category entirely.
An EOR is different from both a PEO and a staffing agency. An EOR is the sole employer of workers placed at your work site, typically in jurisdictions where you don't have a legal entity (e.g., international hiring, or a US company hiring its first employee in a state where it doesn't yet have a registered presence). The EOR is closer to a staffing-agency-like supplied-labor model, but the workers are usually hired specifically for your business rather than placed from an existing labor pool. We sometimes recommend EOR arrangements for clients hiring internationally; for domestic hiring, a PEO is almost always the right answer.
Sometimes yes for short engagements, usually no over multi-year arrangements. A staffing agency markup of 50–80% on a $35/hour worker means the all-in cost is $52–$63/hour. A PEO PEPM of $150/month on the same worker's full-time wage is closer to $0.86/hour at 40 hours/week. The agency markup compounds annually; the PEO fee is bounded. For multi-year relationships, the PEO is dramatically less expensive.
Yes — this is one of the most common "PEO conversion" cases we handle. You convert the agency placements to direct hires, the workers become your employees, and the PEO becomes their administrative co-employer. Timing and W-2 mechanics matter; we plan these transitions to align with quarterly tax cycles.
A 15-minute call sorts out whether your situation calls for a PEO, a staffing agency, an EOR, or something else entirely. No deck, no obligation, no cost.
No. A staffing agency supplies workers it employs to your business on a temporary or contract basis. A Professional Employer Organization (PEO) co-employs your existing workforce — you hired them, you direct their work, and the PEO handles the administrative side. The workers are yours in both economic substance and operational direction; the PEO is just the administrative co-employer for HR purposes.
Both, technically. Under co-employment, the PEO is the W-2 employer of record for federal employment tax purposes (your employees receive W-2s issued by the PEO), but your company remains the common-law employer who directs the work. With a staffing agency, the workers are exclusively W-2 employees of the staffing agency; you are the client, not the employer.
Staffing agencies generally retain more of the legal employment liability because they are the sole employer; PEO arrangements split certain liabilities under joint and several rules (for non-CPEOs) or shift federal tax liability solely to the PEO (for CPEOs). For workers comp, the PEO covers your employees under its master policy; a staffing agency covers its own workers under its own policy. For wrongful termination or discrimination claims, the law varies by jurisdiction but generally treats the co-employer relationship as creating shared exposure under a PEO.
Yes, and many of our clients do. Your core full-time workforce moves to a PEO arrangement; you supplement with staffing-agency contractors for seasonal peaks, specialized project work, or right-to-hire trials. The two arrangements coexist cleanly because they apply to different workers.
Yes. Staffing-agency workers are unambiguously employees of the agency for IRS purposes — the agency files all employment taxes, issues W-2s, and is the sole tax-liable party. PEO workers are treated under the special co-employment rules in IRC Section 3401(d) and (for CPEOs) Section 3511, with the PEO becoming the employer for federal tax purposes. The practical distinction matters for R&D credit claims, WOTC, and certain state tax credits — see our CPEO guide for detail.
Because they solve different problems. A PEO outsources HR administration for employees you already have or plan to hire directly. A staffing agency supplies you with temporary workers. If you need an HR back-office for your full-time team, a PEO is the right answer. If you need a contractor for a 6-month project, a staffing agency is. Conflating them — using a staffing agency as a long-term HR back-office — typically costs more and produces worse outcomes than using a PEO.
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