Choosing the best payroll outsourcing company is usually framed as a comparison of features, service levels and rates, and almost none of that can be verified before you sign. One claim is published, not asserted. The IRS keeps a list of the organizations it has certified, with an effective date next to every name, so the claim can be checked by entity name in the time it takes to open a page.
Everything else a provider says about the filings it covers is checked one jurisdiction at a time, and that checking is more mechanical than it sounds.
Certification Is the Claim With a Public Register Behind It
Start with the word certified, because it is the rare word on a payroll proposal with a federal list underneath it. A certified professional employer organization, or CPEO, is a payroll third party the IRS has certified under a voluntary program, and the statute makes that list public: the Secretary "shall make available to the public the name and address of" each person certified as a CPEO and each person whose certification is suspended or revoked (26 U.S. Code 7705).
The list is a real artifact with a stated cadence. The agency publishes the certified organizations and the effective date of each certification, alongside separate lists of suspended and revoked organizations, and says it "will be updated to reflect newly certified CPEOs by the 15th day of the first month of every calendar quarter" (IRS, CPEO public listings).
So the check itself is dull, which is the point. Take the legal entity name off the draft contract rather than the brand name off the website, find it on the current list, and write down the effective date and the date you looked. A provider that calls itself a PEO but does not appear on that list is not certified. That is a normal thing to be, since the program is voluntary, and what the certification actually buys against the other employment models is set out in employer of record accounting.
A Certification Can Lapse, and the Consequence Lands on the Customer
Certification is a status with an ending attached rather than a permanent badge. An organization stays certified until the IRS revokes its certification or, if earlier, until it voluntarily terminates the certification (IRS, CPEO public listings). It can also be suspended while the relationship is running.
Each of those reaches the customer, and not in the same way. Suspension is the narrowest of the three. Section 3511, which treats the certified organization, and no other person, as the employer of a work site employee for the remuneration it remits (26 U.S. Code 3511), stops applying to any new contract entered during the suspension period, and modifications and extensions of an existing contract are not new contracts, so an arrangement already running keeps the treatment it had. What the customer gets is written notice, within 10 days of the effective date of suspension (IRS, CPEO public listings).
Revocation is the ending that stops the treatment, and its notice rule is the most specific of the three. Within 10 days after the date of the notice of final revocation, and no less than 30 days before the effective date of revocation, the organization has to tell each customer in writing that the IRS has revoked its certification, that the provisions of section 3511 no longer apply to that customer's relationship with it, and that the customer may also be liable, as of the effective date of revocation, for federal employment taxes imposed on remuneration the organization remitted to all employees covered by the customer's contract (IRS, CPEO public listings).
Voluntary termination is the quietest ending, and it still comes with a letter. Before the organization sends its request to the IRS, it has to notify each customer in writing of the intention to terminate and of the proposed effective date, and that notice should include an explanation of the employment tax consequences of termination and a statement that the customer may also be liable, as of the effective date of termination, for federal employment taxes imposed on payments the organization remitted to all employees covered by the customer's contract (IRS, certified professional employer organizations, what you need to know).
Read that as a diligence schedule rather than a scare. Check the register before signing, and again at each renewal, because the status can change while nothing in the contract does. Whether the arrangement in front of you moves employment tax liability at all is the question that comes first, and it is worked through in what a payroll outsourcing case study has to name.
"We Handle All Your Filings" Is One Claim Per Jurisdiction
The federal authorization is a single document, and it is easy to mistake for the whole set. Form 8655 is what a taxpayer signs to authorize a reporting agent to sign and file certain employment tax returns, a grant read clause by clause in how to outsource bookkeeping, and it carries a state or local authorization box at line 19, which authorizes that agent to sign and file state or local returns related to the authorization granted on line 15 and/or line 16 (IRS, Form 8655).
That box is your permission to the agent, and it is filed with the IRS. State agencies run their own authorizations, and they do not all work the same way.
Three States, Three Different Authorizations
California enrolls the agent rather than only the engagement, and the enrollment is elective. The Employment Development Department frames it as a benefit: in place of submitting a Power of Attorney for each client, an enrolled payroll reporting agent keeps one Memorandum of Understanding, Form DE 972, on file with the department, renewable every two years, holds each client's Power of Attorney itself, and each month submits a list of new clients to add and/or clients to delete. Enrolled agencies are listed on the department's online registration site, so a client can select the agency by name when registering a new business (EDD, information sheet on payroll reporting agents).
New York authorizes per taxpayer and per service. Form TR-2000 is how a client authorizes a tax professional to access their account information and perform transactions on their behalf through the Tax Department's Online Services, with the services selected on the form itself. The form does not go to the state. The instruction is "Do not mail the form to the Tax Department", and the professional keeps a copy "for the duration of the authorization plus three years" (New York State Department of Taxation and Finance, E-ZRep Form TR-2000).
Washington puts the approval in the employer's hands, and only for part of the work. Unemployment tax there sits with the Employment Security Department, which says plainly that "You do not need locked services to file unemployment quarterly tax and wage reports or to pay taxes". The account work around filing is what waits on approval, since locked services are what let a user save and amend a report, view payment history and cancel a pending payment. A third party asking for that access picks the term that best describes the relationship, one of "Employee/Delegate", "Third-party authority (TPA)" or "Professional tax preparer", and the request then waits: "An owner or officer of the business with access to locked services will need to approve your access" (Washington Employment Security Department, requesting access to locked services).
Those three do not sit in the same place. California's memorandum is on file with the department, New York's form stays in the professional's own records, and Washington's is an access request inside the employer's account. So turn the sales claim into a list before you compare rates. Name every state you pay people in, and for each one ask what the authorization is, who holds the signed copy, when it was signed, and whether the provider could produce it today.
A provider that has done this before answers with a table. A provider that answers "we handle all of that" is describing an intention rather than an authorization, and what else moves a payroll quote is set out in payroll outsourcing cost.
Shortlisting for Your Clients Is a Different Purchase
A firm buying payroll for itself verifies certification and state authorization once. A firm picking a provider to stand behind its clients does it per client, at every renewal, with its own name on the recommendation.
Three things change in that seat. The register check becomes a recurring control instead of a one-time diligence step, since a status can change between one client's renewal and the next. The authorization inventory multiplies, because the question stops being which states you file in and becomes which states all of your clients file in. And your firm's own position in the arrangement is part of the answer rather than a background fact, which is why the liability question belongs inside the shortlist rather than after it.
Whether the provider's controls hold up is a separate reading exercise, and how to read a SOC report is covered in is outsourcing accounting safe.
There is also the case where none of this applies. If the practice is short of people with hours rather than short of someone to file returns, a payroll company is the wrong purchase. A payroll company sells filing capacity, and it does not give you someone who can close a month, chase a client for a missing timesheet, or reconcile payroll back to the general ledger before a partner sees it.
The Best Payroll Outsourcing Company Is the One Whose Claims Survive a Lookup
Two of the claims on a payroll proposal can be checked before you sign, and the rest are judgment. Certification is looked up on a federal register, by legal entity name, with the effective date recorded next to the date you checked. Filing coverage is checked state by state, one authorization at a time, and for some states the only copy is the one the provider holds. Do those two first, and the sales conversation that follows is about price and fit rather than about trust.
If the shortlist keeps arriving at the same conclusion, that the shortage is people rather than filings, that is a different purchase. Accountably places trained offshore accountants and tax preparers inside US CPA and EA firms, ramped on your software and SOPs in about 3 to 4 weeks. Since 2022 that is 20+ US firms and 30+ placements. Don't trust us. Test us. Run the Free 40-Hour Proof Pilot on a fixed block of your own representative work and grade the output yourself. If a placement is not the right fit in the first 30 days, we replace them free.