PEO and HRO are the two standing models for outsourcing HR, and they differ in structure, not just scope. A professional employer organization enters a co-employment style arrangement: it runs payroll, benefits and HR administration for your whole workforce under its own tax accounts, sold as one bundle per employee. HR outsourcing, HRO, is functional: you hand over chosen processes, payroll processing, benefits administration, recruiting, while remaining the employer in every respect and keeping your own tax accounts and plans. The choice turns on company size, how much employer identity you want to keep, and who should hold compliance risk.
How the PEO model works
A PEO takes on the administrative employer functions for the client's entire workforce: wages paid and employment taxes deposited under the PEO's identification number, benefits provided through the PEO's plans, workers' compensation through its policy, plus HR compliance support. The client keeps direction of the work, hiring and firing. The bundle is the point: a small employer gets payroll discipline and large-group benefits pricing in one contract, priced per employee per month or as a share of payroll. The structural caveat comes from the IRS: with an ordinary PEO the client generally remains liable for federal employment taxes, and only an IRS-certified PEO is treated under section 3511 as sole employer for taxes on wages it remits, so certification is worth verifying before signing.
How the HRO model works
HRO unbundles. You pick functions, payroll processing, benefits administration, recruiting, learning, HR technology, and contract them out individually or as a managed package, while every legal thread of employment stays with you: your EIN on filings, your benefits plans, your workers' compensation policy, your handbook. The provider processes; you remain the employer and the liable party. This suits organisations big enough to have their own plans and rates, where a PEO's pooled pricing adds little, and it scales piecemeal: you can outsource payroll processing alone without moving benefits, which no PEO bundle allows. The corresponding burden is that compliance ownership stays in-house, so an HRO buyer needs an HR function capable of supervising vendors rather than replacing itself with one.
Choosing between them, and the third option abroad
The clean heuristic: a PEO fits smaller employers that want one vendor to carry the administrative employer load and to buy benefits at pooled rates; HRO fits larger employers that keep their own plans and want targeted efficiency in specific processes. The models can be staged, companies commonly outgrow a PEO and move to HRO plus in-house HR once headcount supports their own benefits pricing. Neither model hires abroad: both assume the workers are already employed by a US entity. For a person in a country where you have no entity, the analogous product is an employer of record, which becomes the full legal employer there. This site's verified pricing tables cover both PEO and EOR vendors, so the per-employee cost of each route can be compared directly.
Questions people ask about peo hro
What is the core difference between a PEO and HRO?
Structure. A PEO takes on administrative employer functions for the whole workforce, files under its own tax accounts and provides its own benefits plans. An HRO provider processes chosen functions while you remain the employer of record domestically, with your own accounts, plans and liability.
Which is cheaper, PEO or HRO?
It depends on what the bundle replaces. PEO pricing is per employee per month or a share of payroll, and pooled benefits rates can outweigh the fee for small groups. Larger employers with their own plans usually pay less buying HRO functions individually. Model the total cost per employee both ways.
Does either model remove employment tax liability?
HRO never does; the client remains the employer. A standard PEO does not either, per IRS guidance on third party payers. Only an IRS-certified PEO is treated as the sole employer for federal employment taxes, and only for compensation it actually remits.
Can a PEO or HRO hire employees for me in other countries?
No. Both models assume employment by your own US entity. Hiring where you have no entity is the employer of record model, in which the EOR's local entity is the legal employer; that market and its verified pricing are covered separately on this site.