ASO meaning: administrative services only, in HR and insurance

By the HRPricing editorial teamReviewed October 18, 2026How we research and score

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ASO stands for administrative services only, also called an administrative services organization: a provider handles payroll, benefits or HR administration while your company stays the only employer and keeps the tax liability. In health insurance, an ASO plan means you pay employees' claims yourself and an insurer only administers them. In legal claims, a/s/o means "as subrogee of."

ASO (administrative services only): an arrangement in which a provider performs administrative work, such as payroll, HR or health claims processing, while the client remains the employer or plan sponsor and keeps the financial and legal responsibility.

See TriNet pricing on TriNet’s site
On this page
  1. ASO in HR: you stay the employer
  2. What an ASO costs
  3. ASO health plans
  4. a/s/o in legal and insurance documents

ASO in HR: you stay the employer

An HR ASO runs payroll, benefits administration and HR services, but your company stays the only employer of record. You keep your EIN, state tax accounts, health plan and workers' comp policy. ASO is an industry term, not one defined in the Internal Revenue Code or on the IRS pages we read, so what you get depends on the contract.

ASO vs PEO
ASOPEO
Employer of recordYou aloneShared (co-employment)
Federal employment tax liabilityYoursThe PEO's if it is IRS-certified (26 USC 3511); otherwise generally yours
Health planYour ownThe PEO's pooled plans
Published pricesNone found$79 to $125 per employee a month

Sources: IRS CPEO page; 26 USC 3511; Justworks, Remote and Deel pricing. Checked Oct 16, 2026.

Full comparison: PEO vs ASO. How certification shifts liability: certified PEO.

What an ASO costs

No ASO in our research publishes a price. TriNet sells separate PEO and ASO programs (its referral terms, effective April 3, 2026, list both), so one call can get you both quotes. For a 10-person team, compare any ASO quote against:

  • Gusto Premium payroll with HR tools: $180 + $22 per person = $400 a month.
  • OnPay with Bundled HR: $190 a month.
  • Justworks PEO Basic: $79 per employee = $790 a month.

All checked October 16, 2026, and all exclude taxes and premiums. See payroll software with HR tools, PEO rankings and the HR outsourcing guide.

ASO health plans

In health insurance, an ASO contract goes with a self-funded plan. You pay employees' medical claims from company funds, and an insurer or third-party administrator processes claims and provides its network for a fee. A self-funded employer can also buy stop-loss insurance to cap large claims. A fully insured plan is the opposite: you pay a premium and the insurer carries the claims. Other ways small employers fund health coverage are in small business health insurance.

Frequently asked questions

What does a/s/o mean?
a/s/o means "as subrogee of." It appears in insurance lawsuits where an insurer that paid a claim sues the at-fault party in place of its policyholder.
What does ASO stand for in HR?
ASO stands for administrative services only, or administrative services organization: a provider that runs payroll, benefits administration and HR services while your company stays the only employer and keeps employment tax liability.
What is an ASO health plan?
An ASO health plan is a self-funded plan where the employer pays claims from its own funds and an insurer or administrator processes them for a fee. The employer, not the insurer, carries the claim risk.
What is the difference between an ASO and a PEO?
A PEO becomes your co-employer, pays staff under its tax ID and offers its own benefit plans; if it is IRS-certified it is liable for federal employment taxes on wages it pays (26 USC 3511). With an ASO you stay the only employer with your own plans and liability.
Which companies offer ASO services?
In our research, TriNet sells an ASO alongside its PEO (TriNet referral terms, effective April 3, 2026). No ASO we found publishes a price, so expect a quote.
Sources (9)
  1. IRS: Certified professional employer organization (page last reviewed Jul 15, 2026; checked Oct 16, 2026)
  2. Cornell LII (statute text): 26 USC 3511 (checked Oct 16, 2026)
  3. TriNet: Referral program terms and conditions (effective Apr 3, 2026; checked Oct 16, 2026)
  4. TriNet: TriNet PEO pricing (checked Oct 16, 2026)
  5. Justworks: Justworks pricing (checked Oct 16, 2026)
  6. Remote: Remote pricing (checked Oct 16, 2026)
  7. Deel: Deel pricing (checked Oct 16, 2026)
  8. Gusto: Gusto pricing (checked Oct 16, 2026)
  9. OnPay: OnPay pricing (checked Oct 16, 2026)

This page is general information, not tax, legal or accounting advice. Rules and rates change, so check the official source linked above before you file or sign a contract. Read our disclaimer.