Certification as a Certified Professional Employer Organization (CPEO) affects the employment tax liabilities of both the CPEO and its customers. Proposed regulations PDF provide further details concerning the employment tax liability impacts of certification to CPEOs and their customers. To become and remain certified under the CPEO Program, CPEOs must meet tax status, background, experience, business location, financial reporting, bonding and other requirements described in the statute and regulations. Temporary regulations PDF provide further details concerning certification requirements for CPEOs. As required by law, the IRS will publish lists of CPEOs that have been certified under the program and of those whose certification has been revoked or suspended.