The PEO Question Staffing Agencies Usually Get Wrong

Your internal team, recruiters, account managers, sourcers, operations, is who a PEO would co-employ. The talent you place at client sites is handled through your own employer-of-record infrastructure, or the client's, depending on the placement model, and that's a completely separate system with its own payroll, workers' compensation, and benefits administration that a PEO for your corporate staff doesn't touch at all, even though both systems technically involve running payroll for people your firm has some relationship with.

If your firm is evaluating Justworks or TriNet for the placed workforce specifically, that's usually the wrong tool, since PEOs are built for a single client company's own employees, not a staffing firm's book of worksite employees across multiple client accounts. That's a different kind of relationship, closer to what your firm already provides.

Once you're clear that this is about internal staff only, the Justworks versus TriNet comparison looks like it would for any professional services firm of similar size. Justworks' flat per-employee fee is easy to model against a recruiting team that grows and shrinks with placement volume. TriNet's percentage-of-payroll or custom pricing can work well for a firm with a smaller, more senior internal team and a strong preference for a dedicated HR contact who already understands how a recruiting business runs.

Many recruiting and staffing agencies pay internal recruiters a base salary plus commission tied to placements, which means payroll volume can be genuinely lumpy month to month. Both PEOs handle commission-based pay correctly, but ask each vendor how they handle a payroll run where commission payouts spike significantly in a strong placement month, since that's a different pattern than steady salaried pay.

A related detail worth confirming: how each vendor handles commission clawbacks if a placed candidate doesn't complete a guarantee period and your recruiter's commission needs to be adjusted retroactively. Not every payroll system handles a negative adjustment cleanly.

For the internal, corporate team specifically, payroll tends to run as a meaningful share of the revenue that team's own work generates, consistent with professional services firms generally¹. That's worth tracking separately from your placement business's overall revenue, since blending the two numbers obscures how efficiently your internal team itself is running, and can make a genuinely lean corporate operation look bloated next to total agency revenue that mostly reflects placement fees, not internal team output.

• Confirm which workforce you're actually solving for: internal corporate staff, or placed talent. Only the former is a standard PEO fit.
• If it's placed talent, look at employer-of-record or staffing-specific back-office providers instead, not a general PEO.
• For your internal team, model both vendors' pricing against your actual base-plus-commission structure, not a flat salary assumption.
• Ask each vendor how quickly they can add a new state if your recruiting team is remote and spread out.
• Write down, in one sentence, exactly which people each vendor's quote is meant to cover, so nothing gets confused later.

Staffing is one of the only industries where a business already runs something functionally similar to a PEO, its own employer-of-record operation for placed workers, which makes it easy to assume a standalone PEO product is either redundant with what you already do or somehow meant to replace it. It's neither. Think of it as two entirely separate infrastructure decisions that happen to sit inside the same company: one for the talent you place, which your firm likely already has built or is buying from a specialized provider, and one for the people who run the agency itself, sourcing candidates, managing client relationships, and closing placements.