United States: Overview

1. Ask who will sign the return and what their PTIN is. The person who prepares the return for pay signs it and gives their number; ask for both in writing before the work starts.2Source 2IRS, PTIN requirements for tax return preparers (16 October 2025); 26 U.S.C. 6109(a)(4) and 26 CFR 1.6109-2 (the identifying number is the PTIN); 26 CFR 1.6695-1(b) (the signing preparer signs the return). If the adviser prepares the Form 6765 figures but someone else signs the return, ask who that is and whether they have seen the technical case.
2. Ask what credential each named person holds, and check it. The IRS publishes a directory of preparers with credentials and select qualifications; it lists attorneys, CPAs, enrolled agents and participants in the IRS Annual Filing Season Program who hold a valid PTIN.3Source 3IRS, Understanding tax return preparer credentials and qualifications (29 January 2026) and Choosing a tax professional (21 August 2026), which describes the Directory of Federal Tax Return Preparers with Credentials and Select Qualifications and says that anyone with a PTIN can be a paid preparer. A preparer who is not in it may still be entitled to prepare returns, because the PTIN alone is enough; what a listing tells you is which credential the IRS has recorded for that name. The checking an adviser's credentials page explains how to read it.
3. Ask how the fee is calculated, and whether the adviser is a practitioner under Circular 230. Treasury rules for practitioners who practise before the IRS restrict contingent fees in connection with matters before the IRS, with exceptions. A 2014 US federal court decision stopped the IRS enforcing that rule against the preparation and filing of ordinary refund claims made before an examination starts.4Source 4Treasury Department Circular No. 230, 31 CFR 10.27 (contingent fees, with the exceptions in 10.27(b)(2) to (4)); Ridgely v. Lew, Civil Action No. 1:12-cv-00565 (D.D.C., 16 July 2014), granting a permanent injunction for ordinary refund claims. A proposed rule of 26 December 2024 (Federal Register) would change 10.27; no final rule had been published when this page was checked on 13 October 2026. The rule applies to practitioners, not to every preparer, so the answer depends on who your adviser is. The rules themselves are on the sister site linked beside this page; the contingent success fees page covers what a percentage fee does and does not share.
4. Read the engagement letter against the twenty questions and the contracts section. The engagement letter decides four things: what the fee is a percentage of, what happens to it if the IRS reduces the credit, whether help with an examination is included, and who owns the working papers.
5. Keep the records yourself. The company signs the return and answers for it; the your responsibility page sets out what that means, including the time limits for refund claims and for an IRS assessment.

If the IRS examines the claim, read if your claim is reviewed and take advice before you reply. If the problem is the adviser, the complaints about an adviser page sets out the order: the firm first, then the body that licenses the person, then the IRS, which takes complaints about return preparers on Form 14157.5Source 5IRS, Make a complaint about a tax return preparer (25 September 2026) and Form 14157, Return Preparer Complaint (Rev. 8-2026).

• Checking an adviser's credentials, your responsibility, if your claim is reviewed and complaints about an adviser
• Who is named on the claim? and what qualifications does the team have?
• How to choose an R&D tax adviser

Sources

1. IRS, Form 6765, Credit for Increasing Research Activities (Rev. December 2024), header "Attach to your tax return", and Instructions for Form 6765 (Rev. December 2025).  Back
2. IRS, PTIN requirements for tax return preparers (16 October 2025); 26 U.S.C. 6109(a)(4) and 26 CFR 1.6109-2 (the identifying number is the PTIN); 26 CFR 1.6695-1(b) (the signing preparer signs the return).   Back
3. IRS, Understanding tax return preparer credentials and qualifications (29 January 2026) and Choosing a tax professional (21 August 2026), which describes the Directory of Federal Tax Return Preparers with Credentials and Select Qualifications and says that anyone with a PTIN can be a paid preparer.   Back
4. Treasury Department Circular No. 230, 31 CFR 10.27 (contingent fees, with the exceptions in 10.27(b)(2) to (4)); Ridgely v. Lew, Civil Action No. 1:12-cv-00565 (D.D.C., 16 July 2014), granting a permanent injunction for ordinary refund claims. A proposed rule of 26 December 2024 (Federal Register) would change 10.27; no final rule had been published when this page was checked on 13 October 2026.  Back
5. IRS, Make a complaint about a tax return preparer (25 September 2026) and Form 14157, Return Preparer Complaint (Rev. 8-2026).  Back