What is a certified PEO (CPEO)?

A certified PEO (CPEO) is a professional employer organization that has met rigorous background, financial, and reporting requirements set by the Internal Revenue Service (IRS) under a voluntary certification program. Certification carries a specific legal consequence: under federal law, a CPEO is generally solely liable for paying federal employment taxes on wages it pays to its clients' worksite employees. Clients of non-certified PEOs do not have this statutory safeguard.

As of July 2026, the IRS public listing includes approximately 120 certified legal entities. Because some PEOs certify more than one legal entity, the number of distinct PEO organizations is considerably lower. Based on an analysis of the IRS listing, approximately 60 PEO organizations currently hold CPEO certification, representing about 12% of the roughly 500 PEOs estimated to operate in the United States.

Four financial protections a CPEO provides

1. Sole liability for paying federal employment taxes. When a business pays wages through a non-certified PEO and that PEO fails to remit federal employment taxes, through error, insolvency, or otherwise, the IRS can hold the client liable for unpaid taxes, including penalties and interest. With a CPEO, that risk generally transfers by statute: the CPEO is solely liable for paying federal employment taxes on wages it pays to the client's worksite employees, as defined under IRS rules.
2. An annual surety bond of up to $1 million. To maintain IRS certification, a CPEO must post a bond each year, up to $1 million, guaranteeing payment of its federal employment tax liabilities. The bond exists as protection for the government; the government is paid even if the CPEO cannot pay.
3. No wage-base restart when switching mid-year. Federal payroll taxes such as Social Security (FICA) and federal unemployment (FUTA) apply only up to an annual wage base per employee. When a business joins or leaves a non-certified PEO mid-year, those wage bases restart at zero, meaning taxes already paid on each employee's wages that year are paid again. Certification eliminates the restart, so a business can join or leave a CPEO at any point in the calendar year without duplicate tax exposure. For a company with dozens of employees, this can preserve thousands of dollars and eliminate the need to wait for January to make a change.
4. Preserved eligibility for federal tax credits. CPEO clients retain express statutory authority to claim specified federal tax credits, such as the Work Opportunity Tax Credit and the research and development credit, that they would be entitled to claim if no PEO relationship existed.

What it takes to become IRS-certified

The CPEO program was created by the Small Business Efficiency Act (SBEA), enacted in December 2014, and is administered by the IRS. To earn and keep certification, a PEO must:

• Submit independently audited financial statements annually and maintain positive working capital.
• Pass background and suitability checks on its responsible individuals — the owners, officers and directors who control the organization.
• Demonstrate a history of federal, state, and local tax compliance.
• Meet ongoing quarterly reporting and verification requirements — certification is maintained continuously, not earned once.

The IRS does not endorse any certified professional employer organization.

How to verify that a PEO is certified

The IRS publishes the CPEO Public Listings, updated quarterly, showing every currently certified PEO along with any organization whose certification has been suspended or revoked. Before signing with any PEO that claims certification, businesses (and the CPAs and brokers who advise them) can confirm the claim by reviewing the IRS list. A provider whose name does not appear on the current listing is not a certified PEO, regardless of marketing language.

What is ESAC accreditation?

The Employer Services Assurance Corporation (ESAC) is an independent nonprofit that serves as the official accreditation and financial assurance organization for the PEO industry. Where IRS certification is specifically about federal employment tax responsibility, ESAC accreditation evaluates the broader financial health and operational integrity of a PEO.

Accreditation requires compliance with more than 40 industry best practices and quarterly independent verification of all key employer payments: federal and state employment taxes, health and workers' compensation premiums, and retirement plan contributions. ESAC accreditation is backed by surety bonds that protect clients against a provider's failure to make those payments. Approximately 6%³ of PEOs have achieved accreditation.

Businesses can verify a provider's accreditation status through ESAC's public directory at esacorp.org.

CPEO certification vs. ESAC accreditation: what's the difference?

The two credentials are complementary, not interchangeable. A PEO can hold one, both or neither and the combination of both represents the highest verification standard available in the industry.

ADP TotalSource: certified and accredited

ADP TotalSource® holds both credentials:

• IRS-certified PEO since 2017
• ESAC-accredited since 1995

For TotalSource clients, this means federal employment tax obligations are backed by IRS certification, and key employer payments are independently verified each quarter under ESAC's assurance program in addition to the dedicated HR support, benefits access and compliance guidance of the PEO relationship itself.

Frequently asked questions

Brian Michaud Executive Vice President, Smart Compliance Solutions & Human Resources Outsourcing Brian Michaud helps small and midsized businesses manage their people. He gives them the tools and expertise to attract and retain talent, mitigate employment risks, gain operational efficiencies, and control costs through full-service HR solutions, such as a professional employer organization (PEO) or HR outsourcing (HRO).