PEO vs. ASO: The Real Difference, in Plain English
Both a PEO and an ASO take HR administration off your plate. The difference is one legal concept with big financial consequences: co-employment. A PEO becomes co-employer of your team; an ASO (administrative services organization) just does the work in your name. That single distinction drives everything below.
The comparison
| PEO | ASO | |
|---|---|---|
| Legal structure | Co-employment — the PEO is employer of record for taxes/benefits | You remain sole employer; ASO administers under your EIN |
| Health benefits | Pooled large-group plans — big-company rates for small teams | Your own small-group plans; ASO shops the open market for you |
| Workers' comp | Under the PEO's master policy, pay-as-you-go | Your own policy; ASO may broker it |
| Payroll taxes | Filed under PEO's accounts (a certified PEO takes federal liability) | Filed under your accounts — errors remain yours |
| Compliance risk | Shared with co-employer | Advised, but yours alone |
| Typical cost | $40–160/employee/month | $25–80/employee/month |
| Best at | 5–100 employees wanting benefits power + risk transfer | 100+ employees big enough to self-fund benefits, or teams wanting max control |
The one-question shortcut
"Can I get better health insurance rates on my own?" Under ~75–100 employees, the honest answer is usually no — and the PEO's pooled rates are the whole game (industry research puts average savings around $1,775 per employee per year). Above ~100 employees, your own group is big enough that self-funded or level-funded plans through an ASO can compete — that's when the ASO conversation gets real.
Where the ASO wins
- You're 100+ employees with a benefits history worth underwriting on its own.
- You want zero co-employment — some owners simply prefer sole control of every filing, and that's legitimate.
- You already have great benefits (e.g., through an association or union arrangement) and only need the admin muscle.
Where the PEO wins
- 5–100 employees buying health insurance — pooling beats the small-group market for most companies most years.
- Multi-state teams — risk transfer plus fifty-state compliance in one contract.
- Higher-risk industries — master-policy workers' comp pricing is hard to beat solo.
Worth knowing: many national providers (ADP, Paychex, Insperity) sell both models, and companies commonly graduate from PEO to ASO as they scale past 100–150 employees. Choosing today isn't forever.
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