PEO Services: What's Included, What's Extra, and Who Does Each Well

Five service categories are universal across full-service PEOs: payroll, benefits, HR administration, compliance, and workers' comp. A sixth — HR technology — is bundled with every PEO but varies wildly in quality. The depth and execution within each category is where the real differentiation lives.

The marketing copy across PEOs is uniform. The actual service delivery isn't. We've seen contracts where "HR support" meant a phone number and a 48-hour ticket queue. We've seen "compliance" mean a poster shipment once a year. Buyers who don't pressure-test each line item end up paying premium PEPM for budget service.

The rest of this guide breaks down what good looks like in each category, who delivers it well, and the line-items that should be in your CSA but rarely show up by default.

Every PEO does payroll. The differences come in three dimensions: multi-state complexity handling, technology platform UX, and tax-filing accuracy.

Multi-state operational depth. Insperity, ADP TotalSource, and CoAdvantage have the deepest state-by-state operational footprints. A 50-state operator on TriNet typically gets cleaner reporting than the same operator on a younger budget PEO like Justworks (whose multi-state engine is solid but newer). For companies operating in unusual or monopolistic workers' comp states (Ohio, Washington, Wyoming, North Dakota), check that the PEO has a working relationship with the state fund — not all do.

Platform UX. Rippling and Justworks lead on modern interfaces. ADP and Insperity offer the deepest configurability but with older UX patterns. Gusto sits between — modern UX, less feature depth. If your HR team has spent 5+ years on a legacy HRIS, ADP's platform will feel familiar; if they've only known Rippling and Notion, ADP will feel like a step backward.

Tax-filing accuracy. This is where bad PEOs get expensive. We've seen a 30-employee New York client hit with $14K in penalties because their PEO missed three quarterly New York filings. CPEO status (IRS-certified) is the strongest single screen for this — CPEOs maintain quarterly tax-compliance attestations and assume sole liability for federal employment taxes.

Full breakdown: PEO payroll services.

This is the section most buyers don't realize matters until they're in a contract.

Master plan means you join the PEO's existing carriers (Aetna, UnitedHealthcare, Anthem, BCBS, Kaiser) at the PEO's negotiated rates. You don't pick your carrier, plan design, or network — you join what's there. Master plans are where the cost savings live: a 25-person agency joining Insperity's master plan typically sees 15–30% lower premiums than they'd get standalone, with deeper networks.

Carve-out plan means the PEO administers your existing benefits — your carriers, your plan designs, your broker relationship — but doesn't deliver them through their master plan. Carve-out preserves flexibility (you keep your benefits broker, you keep custom plan designs) but eliminates the buying-power advantage. We typically see carve-out save 0–5% on benefits administration but cost the same on premium.

Master plans are about 80% of the PEO market. Carve-out is more common above 200 employees, where the buyer has its own broker leverage and doesn't want to lose it. If you're evaluating PEOs and the proposal doesn't specify which model — ask. Sales reps default to "whichever you want," then quietly route you into master plan during onboarding because it's easier on their side.

Full breakdown: PEO benefits administration.

What "HR compliance" actually means inside a PEO contract:

• Labor law poster updates (table stakes — every PEO does this)
• ACA reporting (Forms 1094-C and 1095-C transmittals)
• I-9 verification workflow + E-Verify integration
• Multi-state employment law guidance (varies by depth)
• ERISA / 401(k) compliance for the PEO's group plan
• EPLI policy (Employment Practices Liability Insurance) — typically $1M–$3M limit
• Workplace harassment training modules
• Sometimes: ADA accommodation support, FMLA tracking, paid leave compliance

What's usually NOT included:

• Defending discrimination lawsuits (covered by EPLI, but you co-pay the deductible)
• Workplace investigations (your HR or outside counsel)
• Wage-and-hour audit defense
• State-specific labor law training for managers (often an upsell)
• Background check workflows above basic E-Verify (usually a separate vendor)

The EPLI limit matters more than buyers usually appreciate. A $1M EPLI cap can be eaten by a single significant employment lawsuit. For companies with 100+ employees or in litigious jurisdictions (California especially), supplemental EPLI is often worth it — typically $3K–$8K annually for $2M–$5M in additional coverage.

Full breakdown: PEO HR compliance services.

For industries with workers' comp exposure — construction, manufacturing, healthcare, trucking — this is often the single biggest ROI driver in a PEO decision.

How PEO workers' comp works. The PEO maintains a master policy with one or more workers' comp carriers. Your employees roll under that master policy at the PEO's blended experience modification rate. The PEO's blended mod is typically <1.0 (rates below the industry average) because it's an aggregate across thousands of clients — your individual claim history doesn't set the rate, the pool does.

The math for high-mod-rate clients. A 75-employee Texas plumbing contractor with a standalone mod of 1.34 pays the contractor base rate × 1.34. The same employer joining a PEO whose blended mod is 0.92 pays the same base rate × 0.92. On a $400K annual workers' comp premium, that spread is $168K/year in difference. For high-mod industries, the workers' comp savings alone often pays for the PEO PEPM 2–3x over.

The tradeoff. You're joining a pool. If your safety program is excellent and your mod is already below 0.85, the PEO's blended pool rate may actually be higher than what you can get solo. The PEOs to look at if you have a great safety program: those that offer industry-specific groups (CoAdvantage has dedicated construction and healthcare pools) where your peer comparison is tighter and good safety performance is rewarded.

Full breakdown: PEO workers' comp management.

Risk management is the umbrella over compliance, workers' comp, and employment liability. The mature PEOs treat it as a proactive service; the budget ones treat it as a reactive insurance pool. The difference matters during a claim.

Proactive risk management includes: site safety audits, OSHA compliance reviews, return-to-work programs after injuries, claims-management consulting, mock OSHA audits, and structured safety incentive programs. Insperity, ADP TotalSource, and TriNet offer these for mid-market and enterprise tiers; budget PEOs typically don't.

Reactive support includes: claims-filing assistance after an incident, EPLI deductible support, OSHA-citation defense, and unemployment-claim hearings. Every PEO offers this baseline.

For construction, manufacturing, and other high-risk industries, the proactive vs reactive distinction is often a 15–25% difference in long-run workers' comp premium and a much larger difference in lost-time injury rates. Buyers focused only on PEPM pricing miss this entirely.

Every PEO ships with an HR tech platform — a portal where employees check their pay stubs, enroll in benefits, request time off, access W-2s, and where HR runs reports. Quality ranges from "decent SaaS" to "looks like 2008."

Modern UX leaders: Rippling (best-in-class), Justworks (clean, lean), Gusto (good for sub-100 EE), TriNet (newer interface, improving). Best for: HR teams that have used modern SaaS in the last 3–5 years.

Deep configurability: ADP TotalSource, Insperity Premier, CoAdvantage. Best for: complex multi-entity structures, deep payroll customizations, mature HR teams that need granular control.

Integration ecosystem. Rippling leads on native integrations (Slack, Greenhouse, Lattice, Notion, etc.). Most legacy PEOs have an API but limited pre-built integrations — your engineering or RevOps team will need to build connectors.

Mobile experience. Justworks, Gusto, and Rippling have strong mobile apps employees actually use. Older PEOs typically have mobile interfaces that work but feel like adapted desktop screens.

The platform isn't the whole PEO decision but it's a daily-touch artifact. If your team will hate using it every day, that influences renewal decisions 2–3 years out. Full breakdown: PEO HR technology platform.

This is the section nobody at a PEO will volunteer. PEPM advertised pricing covers the bundled core — but a chunk of what HR teams actually need is sold as add-on. Common upcharges:

• Recruiting / ATS — usually a separate platform (Lever, Greenhouse) or PEO-provided ATS at $20–80 PEPM extra
• Learning management system (LMS) — basic harassment-training compliance LMS included; deeper L&D is upsell
• Custom HRIS integrations — Rippling-tier integrations are free; everywhere else, integration projects are billed at $5K–$25K + ongoing maintenance
• Dedicated account manager — usually pooled support below 75–100 EE; dedicated AM is a premium-tier feature
• Strategic HR consulting — typically $30–80 PEPM extra for ongoing advisor time
• Compensation & benefits benchmarking — usually a one-off project ($3K–$10K) or premium-tier inclusion
• M&A due-diligence support — every M&A event is custom-priced; expect $5K–$25K for a clean PEO handoff
• Workplace harassment training above the compliance minimum — usually an upsell
• EAP (Employee Assistance Program) — sometimes included at premium tier; often separate
• Mental health and wellness benefits — typically separate carrier add-ons

None of these are wrong to charge for. The trap is assuming they're in the bundle and discovering at signing they're not. Ask the rep to enumerate what's NOT in your PEPM, in writing, before you sign the CSA.

Three questions surface real service quality faster than any sales deck:

1. "What's your customer-success SLA, and where is it documented in the CSA?" Most PEOs have no SLA in the CSA. The good ones will reference response-time targets (24-hour first-touch, 72-hour resolution) and have a service-credit framework when they miss. The absence of any SLA isn't a deal-breaker, but it tells you support quality is "as-good-as-we-feel-like."

2. "What's your federal and state tax-filing error rate over the last 12 months?" The CPEOs publish this. Premium PEOs can answer the question. Budget PEOs typically can't — which is itself a data point.

3. "How many of your CS reps will be dedicated to my account vs pooled across other clients?" Pooled support is fine for budget-tier service. You should know which model you're buying. The phrase to listen for: "you'll have a primary point of contact" is salesperson code for "pooled with a name." Dedicated means dedicated.