Payroll & Benefits
The Best ASO Services of 2026
A shortlist of administrative services organizations (ASOs) ranked from verified service data: who runs payroll and tax filing under your own accounts, who administers the benefit plans you keep, and how much HR help comes with it. Each score traces to a fact we checked on the provider's own pages.
- products compared
- 8
- with a published score
- 0
- last updated
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ASO Services ranked by LeadChange Score
None of these products has enough verified facts for a LeadChange Score yet, so none is ranked: they are listed by the share of their facts we have verified. Prices are list prices as published by each vendor.
Filter by verified facts
ADP Comprehensive Services
Best for Employers with 25 or more employees that want to outsource HR administration but stay the employer of record
ADP Comprehensive Services is ADP's modular HR outsourcing service for employers with 25 or more employees: designated HR, payroll, benefits and talent specialists on the ADP Workforce Now suite, while the business stays the sole employer of record.
- Pricing model
- Quote only
Not scored yetC2 Essentials ASO
Best for Federal and government contractors that need SCA, AAP, EEO-1 and VETS-4212 support
C2 Essentials, based in Ashburn, Virginia, sells a PEO and an ASO aimed at government contractors; its ASO keeps the client as sole employer of record and covers payroll and tax administration, benefits management of client-sponsored plans and federal contractor compliance such as affirmative action plans and SCA…
- Pricing model
- Quote only
Not scored yetConnor & Gallagher OneSource ASO
Best for Small and mid-size businesses juggling separate payroll, HR, benefits, retirement and insurance vendors
Connor & Gallagher OneSource (CGO), founded in 1997 as an insurance agency, sells an ASO that bundles UKG Ready payroll and HRIS with HR management outsourcing, employee benefits, retirement plan services and workers' compensation, while the client remains the employer. UKG Ready is required and pricing is quoted.
- Pricing model
- Quote only
Not scored yetEaseworks ASO
Best for California employers that want to stay the employer of record
Easeworks is a California HR outsourcing firm, operating since 2000, whose ASO keeps the client as sole employer while Easeworks runs payroll and tax support, HR administration, compliance workflows and reporting with a named HR partner.
- Pricing model
- Quote only
Not scored yet
XcelHR ASO
Best for Small businesses that want payroll tax filing and HR help without co-employment
XcelHR, a PEO serving small businesses for more than 30 years, also sells an ASO: the client remains employer of record, XcelHR files payroll taxes under the client's FEIN, and it adds HR compliance help, benefits arrangement and recruiting support on its cloud HR software. Prices are not published.
- Pricing model
- Quote only
Not scored yet
AsureWorks
Best for Small and mid-size employers that want payroll run for them without a PEO
AsureWorks is Asure Software's managed payroll and HR administration service: Asure specialists run payroll, tax filing and reporting, records and onboarding on AsureCentral while the client remains employer of record with no co-employment. It does not bundle benefits, and pricing is quoted.
- Pricing model
- Quote only
Not scored yet
guHRoo ASO
Best for Small businesses that already have their own benefits providers
guHRoo (Executive Resource Group, South Carolina) publishes the price of its ASO plan, Professional Payroll & HR: $79 per employee per month with a $1,000 monthly minimum and an implementation fee of two months' billing.
- Pricing model
- Per employee
VertiSource HR ASO
Best for Employers that want payroll plus HR administration while staying sole employer of record
VertiSource HR, a Utah-based PEO serving all 50 states, sells ASO Plus: payroll and tax, HRIS and records, HR administration, part of benefits administration and HR compliance support, without co-employment and under the client's own tax ID. Its pricing page builds a service estimate but no dollar price.
- Pricing model
- Quote only
Not scored yet
LeadChange Score: editorial assessment based on public information.
Find your fit
Compare and price
By industry
- Best administrative services organization for construction
- Best administrative services organization for government
- Best administrative services organization for healthcare
- Best administrative services organization for hospitality
- Best administrative services organization for logistics
- Best administrative services organization for manufacturing
How to choose ASO services
6 criteria · Requirements by company size · 5 red flags
An ASO is a service contract: you buy specific HR and payroll work while keeping the employer's obligations. Choose for what the fee covers, who does the work and what stays with your own team.
Ask every provider for the list of included services, the add-ons with their fees and a sample invoice for your headcount before you compare prices.
Tax responsibility in writing
With an ASO, payroll taxes are filed under your company's EIN. The IRS says a payroll service provider or reporting agent assumes no liability for its clients' employment tax duties, so a missed deposit is still yours.
What the per-employee fee includes
ASO fees are usually a per-employee monthly charge for the services you select, and many features are sold as add-ons, so two quotes with the same rate can cover different work.
Benefits administration for your own plans
You keep sponsoring your own benefit plans, so the ASO's value is in enrollment, eligibility, ACA and COBRA administration and carrier connections for those plans.
Depth of HR advice
Support ranges from an on-demand HR line to a dedicated HR business partner, and the difference shows in terminations, leave and handbook questions.
Workers' compensation
An ASO does not provide its own workers' compensation coverage: you keep your policy, and some ASOs help administer it.
Technology and data ownership
Your team and employees use the platform every day, and you keep the employer's records when you leave.
Requirements by company size
Small businesses
- A base fee that covers payroll, tax filing and benefits administration
- An HR line that answers real employee questions
- A clear list of add-ons and their prices
Watch out for
- Minimum headcounts that exclude very small teams
- Core payroll features sold as add-ons
- Expecting PEO-style group benefits from an ASO
Mid-sized companies
- Services you can add or drop as your HR team grows
- Benefits administration that connects to your own carriers
- Reporting and data export for finance and HR
Watch out for
- Per-employee fees that grow faster than the work you hand over
- Advisory hours capped in the base fee
- Platform limits for multi-state or multi-entity payroll
Enterprises
- Modular services by function: payroll, benefits, HR or talent
- Named specialists and business reviews
- Clear terms on data, audit rights and service levels
Watch out for
- Overlap with work your in-house HR team already does
- Separate fees for integrations and global payroll
- Unclear ownership of tax notices and corrections
Red flags
- The provider cannot say in writing who files and deposits your payroll taxes and how you can check each deposit.
- The quote shows one per-employee rate but no list of what it includes.
- The provider describes its service as an ASO but asks you to move employees onto its own EIN or its benefit plans, which is how a PEO works.
- Exit terms restrict access to your own payroll history or tax records.
- Savings claims are not tied to your actual headcount and services.
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Learn
- GuideASO vs PEO
ASO vs PEO compared: co-employment, whose EIN files payroll taxes, benefits, workers' comp and fees, plus a checklist to choose.
Glossary
Frequently asked questions
What is an administrative services organization (ASO)?
An ASO is an HR outsourcing provider that handles payroll, payroll tax administration, benefits administration, HR guidance and compliance support without becoming a co-employer. Your business stays the only employer: payroll taxes are filed under your own EIN and you sponsor your own benefit plans.
What is the difference between a PEO and an ASO?
Co-employment. A PEO co-employs your staff, reports wages under its own EIN and gives access to its large-group benefits and, usually, its workers' compensation coverage. An ASO does not co-employ: it files payroll taxes under your EIN, administers the benefit plans you sponsor, and you keep your own workers' compensation policy.
Who is liable for payroll taxes with an ASO?
Your business. The IRS says a payroll service provider or reporting agent files using each client's EIN and assumes no liability for the client's employment tax duties. A certified PEO (CPEO) is different: it files aggregate returns under its own EIN and is generally solely liable for the federal employment taxes on the wages it pays.
Does an ASO provide workers' compensation insurance?
No. With an ASO you keep your own workers' compensation policy; some ASOs help administer it. A PEO usually provides or arranges workers' compensation coverage for its clients' employees as part of co-employment.
Does ASO mean self-funded?
Only in health insurance. There, ASO stands for «administrative services only»: the employer self-funds its health benefits and a third party manages the plan. An administrative services organization is an HR outsourcing provider for payroll, benefits administration and HR support, and it does not fund or insure health plans.
Is ADP a PEO or an ASO?
Both, as separate products. ADP TotalSource is ADP's PEO, which uses co-employment. ADP Comprehensive Services is its outsourcing service where the business remains the sole employer of record and ADP does not share employment liability.
Is Insperity a PEO or an ASO?
Insperity sells both models. Its HR360 and HRScale plans are PEO services through co-employment. Insperity HRCore is an HR platform with HR support that Insperity describes as independent of the professional employer organization model.
Can you switch from a PEO to an ASO?
Yes. Businesses can move from a PEO to an ASO, or the other way, subject to the service agreement and payroll tax reporting requirements. Several providers sell both, including ADP, TriNet, Insperity and Paychex, which can make the move simpler; plan it around your benefits renewal date.
What size business is an ASO best for?
An ASO suits businesses that already have someone responsible for HR and want administrative help while keeping control. CO— suggests a PEO when the owner handles HR alone, and an ASO once one or more people are responsible for HR functions.
How we research
Ranked by the LeadChange Score, computed only from verified facts: capability coverage (30%), pricing and value (20%), integrations and API (15%), security (15%), fit and support (10%) and data confidence (10%), times a category fit. Products with too few verified facts are not scored yet and come last. Payment never changes a score or a position.
Facts, not impressions · Missing data is never assumed · Independent of revenue
Facts, not impressions
Every input is a fact verified against vendors’ official documentation, with the date we last checked it.
Missing data is never assumed
Unverified items are left out of the score and lower its coverage; below 60% coverage a product is not scored yet.
Independent of revenue
Rankings never depend on whether a vendor pays us.
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