TriNet Group, Inc. is a Dublin, California-based professional employer organization for small and medium-sized businesses. TriNet administers payroll and health benefits and advises clients on employment law compliance and risk reduction, acting in some cases as an outsourced human resources department. TriNet is headquartered in. TriNet partners with organizations between 3 and 2,500 employees. Founded in 1988, TriNet offered basic employee benefits, dental coverage, life and disability insurance and employment law guidance. Since then, TriNet has broadened its offerings to add payroll services, Fortune-500 benefits, 401 guidance, worker's compensation, liability insurance, and strategic human resources support and services. The company also provides online tools such as web-hosted management portals for manager and employee self-service. TriNet has been accredited by the Employer Services Assurance Corporation since 1995. Wikipedia