An administrative services organization (ASO) is an organization that provides outsourced solutions to meet the administrative and HR needs of the client, with the client retaining all employment-related risks and liabilities. The term ASO was established by the PEO industry in the late 1990s in order to distinguish between selective administrative support and full-scale PEO services. The principal difference between the two types of service is that, in an ASO arrangement, the employer remains the employer of record for tax purposes. Ultimately, with this structure, tax and insurance filings are done through the administrative firm, but under the client company's employer identification number. All W-2 and workers' compensation policies remain the responsibility of the employer and not the administrative firm.Some of the more common administrative services offered are payroll processing, payroll administration, benefits administration, and corporate benefits.

Payroll services include- W-2 processing, tax filing services, direct deposit, wage garnishment, new hire reporting, standard & custom reports, HRIS, expense reporting, employee time & attendance, paycards, pay as you go workers comp, 401(k) administration, & unemployment Cost Control.Benefits administration includes- managing COBRA, HRA/ HSAs, FSAs and transit pre-tax plans, bill payment/ premium reconciliation, & benefits enrollment.Corporate benefits include- organizing/ negotiating health insurance, group dental, STD, LTD, life, etc.