United States: Checking an adviser's credentials

Anyone who prepares, or helps prepare, a federal tax return for pay must have a valid preparer tax identification number from the IRS for the year in question.1Source 1IRS, PTIN requirements for tax return preparers (16 October 2025): "Anyone who prepares or assists in preparing federal tax returns for compensation must have a valid 2026 PTIN before preparing returns". A paid preparer signs the return they prepare and puts the number on it, and the law sets a penalty for each failure to do either, unless there was reasonable cause.2Source 226 U.S.C. 6109(a)(4); 26 CFR 1.6109-2(a); 26 CFR 1.6695-1(b); 26 U.S.C. 6695(b) and (c); IRS, Tax preparer penalties (21 September 2026): $60 for each failure to sign or to furnish the number for returns filed in 2025, up to $31,500 a year. The research credit is worked out on Form 6765, which has no preparer signature of its own; the preparer signs the return the form is attached to.3Source 3IRS, Form 6765 (Rev. December 2024), "Attach to your tax return"; Instructions for Form 6765. So the first question is simple: who will sign the return, and what is their PTIN?

The IRS describes several kinds of preparer, and the differences matter when you are choosing one.4Source 4IRS, Understanding tax return preparer credentials and qualifications (29 January 2026).

• Enrolled agents are licensed by the IRS itself, after a suitability check and a three part examination, and may represent clients before the IRS.
• Certified public accountants are licensed by state boards of accountancy, the District of Columbia and the territories.
• Attorneys are licensed by state courts.
• Annual Filing Season Program participants have completed a voluntary IRS program; it is not a licence.
• PTIN holders with no credential may prepare returns, because the PTIN is all the law requires; the IRS says that anyone with a PTIN can be a paid preparer.5Source 5IRS, Choosing a tax professional (21 August 2026): "Anyone can be a paid tax return preparer as long as they have an IRS Preparer Tax Identification Number (PTIN)"; the page describes the directory and who it lists.

Enrolled agents, CPAs and attorneys are practitioners under Treasury Circular 230, the rules of practice before the IRS, which among other things restrict contingent fees for matters before the IRS and are enforced by the IRS Office of Professional Responsibility.6Source 6Treasury Department Circular No. 230, 31 CFR Part 10, including 10.27 (contingent fees); IRS, Office of Professional Responsibility and Circular 230 (28 May 2026): OPR investigates and disciplines violations of Circular 230, which covers mainly attorneys, CPAs and enrolled agents. A preparer with only a PTIN is not bound by those rules in the same way. Which kind of preparer suits you is your decision; what you should not do is assume a credential that has not been shown.

The IRS keeps a Directory of Federal Tax Return Preparers with Credentials and Select Qualifications. It lists attorneys, CPAs, enrolled agents, enrolled retirement plan agents, enrolled actuaries and Annual Filing Season Program participants who hold a valid PTIN, and the IRS says it helps you find preparers in your area who hold a credential the IRS recognises.5Source 5IRS, Choosing a tax professional (21 August 2026): "Anyone can be a paid tax return preparer as long as they have an IRS Preparer Tax Identification Number (PTIN)"; the page describes the directory and who it lists. For a CPA, ask the state board of accountancy that issued the licence about its status. Ask the adviser for the names of the people who will do the work and the state of each licence, then look them up.

A directory entry tells you that a person holds the credential shown and a current PTIN. It does not tell you whether they have prepared research credit claims before, how the technical case will be written, who on their team will talk to your engineers, or what their fee covers. A person who is not in the directory is not necessarily doing anything wrong, because a PTIN alone is enough to prepare returns. If a name is not in the directory, do not assume a credential. Ask which credential the person holds and who issued it, and check with that body. Those are reasons to ask more questions, not conclusions.

• Who will sign the return, and what is their PTIN?
• Which of the named people is an enrolled agent, a CPA or an attorney, and in which state?
• Will the person who writes the technical case talk to the people who did the work? (Who will do the technical work?)
• Do you pay or receive referral fees for introductions, and will you disclose them in writing? Members of the AICPA who pay or accept a referral fee must disclose it to the client.7Source 7AICPA, Code of Professional Conduct, ET section 1.520, Commissions and Referral Fees, rule 1.520.001 paragraph .04 and interpretation 1.520.080 (disclosure in writing), edition through September 2026. State boards of accountancy can set stricter rules.

• What qualifications does the team have? and named people with qualifications you can check
• Your responsibility and complaints about an adviser in the United States
• Reference check guide

Sources

1. IRS, PTIN requirements for tax return preparers (16 October 2025): "Anyone who prepares or assists in preparing federal tax returns for compensation must have a valid 2026 PTIN before preparing returns".  Back
2. 26 U.S.C. 6109(a)(4); 26 CFR 1.6109-2(a); 26 CFR 1.6695-1(b); 26 U.S.C. 6695(b) and (c); IRS, Tax preparer penalties (21 September 2026): $60 for each failure to sign or to furnish the number for returns filed in 2025, up to $31,500 a year.  Back
3. IRS, Form 6765 (Rev. December 2024), "Attach to your tax return"; Instructions for Form 6765.  Back
4. IRS, Understanding tax return preparer credentials and qualifications (29 January 2026).  Back
5. IRS, Choosing a tax professional (21 August 2026): "Anyone can be a paid tax return preparer as long as they have an IRS Preparer Tax Identification Number (PTIN)"; the page describes the directory and who it lists.   Back
6. Treasury Department Circular No. 230, 31 CFR Part 10, including 10.27 (contingent fees); IRS, Office of Professional Responsibility and Circular 230 (28 May 2026): OPR investigates and disciplines violations of Circular 230, which covers mainly attorneys, CPAs and enrolled agents.  Back
7. AICPA, Code of Professional Conduct, ET section 1.520, Commissions and Referral Fees, rule 1.520.001 paragraph .04 and interpretation 1.520.080 (disclosure in writing), edition through September 2026. State boards of accountancy can set stricter rules.  Back