US vs Ireland | Research Credit Integrity Alliance

This page sets the federal research credit in the United States beside the R&D corporation tax credit in Ireland. It compares how advisers may be paid, how preparers are registered and identified, and the checks, penalties and appeal routes that apply to claims. Each country page gives the fuller rules and sources.

This table simplifies each country's rules for comparison. See the country pages for detail and sources. Last reviewed pending.

Topic	United States	Ireland
Tax authority	Internal Revenue Service (IRS), part of the Treasury Department1	Revenue (the Revenue Commissioners)2
Scheme	Credit for increasing research activities under Section 41, claimed on Form 676534	R&D corporation tax credit under section 766C TCA 1997, 30 percent for accounting periods beginning on or after 1 January 2024, claimed on Form CT125
Rules on adviser fees	Circular 230 generally bars contingent fees for practitioners, with exceptions6; a 2014 court decision limited it for refund claims filed before an audit7; a 2024 proposal to replace it was not final8	No rule on how preparers are paid in section 766C or Revenue's R&D and agent guidance259; agents may not receive clients' business tax refunds directly9
Professional body rules	AICPA members in public practice may not prepare an original or amended return or refund claim for a contingent fee10	Chartered Accountants Ireland treats contingent fees as a possible threat to objectivity and prohibits them for audits11; the Irish Tax Institute recommends no method of charging12
Adviser registration	Paid preparers need a preparer tax identification number (PTIN); no examination is required1314	No Revenue approval system for agents; an agent needs a Tax Advisor Identification Number (TAIN) and a client link9
Preparer identification	The signing preparer's PTIN, and the firm's number where relevant, go on the return or refund claim15; Form 6765 has no preparer field16	The details required with a claim do not include the preparer517; whether Form CT1 records one is not stated
Claim integrity measures	No advance notice4; refund claims must list business components, research activities and expense totals18; Section G business component detail required for tax years beginning after 2025, with exceptions4	Pre-filing notification at least 90 days before a first claim, or after three periods without one517; a claim must include all information Revenue may reasonably require5
Penalties	20 percent accuracy-related penalty19; 20 percent of an excessive refund claim20; preparer penalty of the greater of $1,000 or 50 percent of income derived21	Unauthorized amounts charged to tax on four times the amount, with tax-geared penalties under section 1077F522; penalty under section 1055 for deliberately assisting an incorrect return23
Reviews and disputes	IRS checks each research credit refund claim for validity24; Independent Office of Appeals, then the Tax Court or a refund suit25; claims rejected as deficient cannot go to Appeals26	Science and accounting tests22; Revenue may consult independent experts27; interventions under Revenue's Code of Practice; appeals to the Tax Appeals Commission28

Where they differ

Fees. The United States restricts contingent fees for practitioners through section 10.27 of Circular 230, limited by a 2014 court decision for refund claims filed before an audit.67 Section 766C, Revenue's R&D manual and its guidelines for agents contain no rule on the basis on which a claim preparer may be paid.259 Revenue's guidelines do state that agents may not receive their clients' business tax refunds directly.9 See Contingent fee rules by country.

Professional bodies. The AICPA Code bars its members in public practice from preparing returns or refund claims for a contingent fee.10 Chartered Accountants Ireland prohibits contingent fees for audit engagements and treats them otherwise as a possible threat to objectivity, and the Irish Tax Institute leaves the method of charging to its members.1112

Registration and identification. A paid US preparer needs a PTIN, and the signing preparer's PTIN goes on the return or refund claim.1315 Revenue operates no approval system for agents; an agent acts through a TAIN and a client link.9 The details Irish law requires with a claim do not include the identity of anyone who helped prepare it.517

Timing. The United States requires no advance notice of a claim.4 In Ireland, first-time claimants and companies with no claim in the previous three accounting periods must notify Revenue at least 90 days before claiming.517 See Claim integrity measures by country.

Penalties. US penalties on the business include a 20 percent accuracy-related penalty and a penalty of 20 percent of an excessive refund claim.1920 In Ireland an unauthorized amount can be charged to tax on four times that amount, with tax-geared penalties under section 1077F.522

Where they are similar

Neither country's claim requirements ask how the preparer was paid. Form 6765 and its instructions do not ask who prepared the calculation or how that person was paid, and no Irish source reviewed requires the claim, the notification or the return to state the preparer's fee basis.418517

Both reach people who help with an incorrect return. The United States penalizes any person who aids or advises on a return knowing it would understate another person's tax, and Ireland's section 1055 penalizes a person who deliberately assists in or induces an incorrect return.2923 See Penalties by country.

Both require claims to carry detailed support: business components, research activities and expense totals for a US refund claim, and for an Irish claim all the information Revenue may reasonably require.185

Both have an appeals body for disputes: the IRS Independent Office of Appeals, followed by the courts, and the Tax Appeals Commission in Ireland.2528 See Disputes and appeals by country.

Sources

Internal Revenue Service, Publication 5, Your Appeal Rights and How to Prepare a Protest if You Disagree (Rev. 4-2021), page 1 footer ("Department of the Treasury Internal Revenue Service"). https://www.irs.gov/pub/irs-pdf/p5.pdf (accessed 11 October 2026). Back
Revenue Commissioners, Tax and Duty Manual Part 29-02-03, Research and Development (R&D) Corporation Tax Credit (last updated April 2026), section 1 and section 2.6. https://www.revenue.ie/en/tax-professionals/tdm/income-tax-capital-gains-tax-corporation-tax/part-29/29-02-03.pdf (accessed 11 October 2026). Back
Office of the Law Revision Counsel, 26 U.S.C. 41, Credit for increasing research activities, subsections (a) and (c)(4)(A), United States Code 2024 edition published by the Government Publishing Office. https://www.govinfo.gov/content/pkg/USCODE-2024-title26/html/USCODE-2024-title26-subtitleA-chap1-subchapA-partIV-subpartD-sec41.htm (accessed 11 October 2026). Back
Internal Revenue Service, Instructions for Form 6765 (Rev. December 2025), What's New, Purpose of Form, "Requirements To Complete Section G" and "Research Credit Claims on Amended Returns". https://www.irs.gov/instructions/i6765 (accessed 11 October 2026). Back
Revenue Commissioners, Notes for Guidance, Taxes Consolidation Act 1997, Finance Act 2025 edition, Part 29, section 766C, subsections (1), (6), (7), (9), (10), (14) and (17). https://www.revenue.ie/en/tax-professionals/documents/notes-for-guidance/tca/part29.pdf (accessed 11 October 2026). Back
Treasury Department, Circular No. 230, 31 CFR 10.27, Fees, paragraphs (b)(1) to (b)(4) and (c)(1) to (c)(2), with source note T.D. 9359 (eCFR text up to date as of 8 October 2026). https://www.ecfr.gov/current/title-31/subtitle-A/part-10/subpart-B/section-10.27 (accessed 11 October 2026). Back
US District Court for the District of Columbia, Ridgely v. Lew, Civil Action No. 1:12-cv-00565 (CRC), Memorandum Opinion, 16 July 2014, pages 1 and 14 to 15. https://www.govinfo.gov/content/pkg/USCOURTS-dcd-1_12-cv-00565/pdf/USCOURTS-dcd-1_12-cv-00565-1.pdf (accessed 11 October 2026). Back
Treasury Department and Internal Revenue Service, Regulations Governing Practice Before the Internal Revenue Service, notice of proposed rulemaking, 89 FR 104915 (26 December 2024), Dates, Explanation of Provisions part B and proposed section 10.51(b). https://www.federalregister.gov/documents/2024/12/26/2024-29371/regulations-governing-practice-before-the-internal-revenue-service (accessed 11 October 2026). Back
Revenue Commissioners, Tax and Duty Manual Part 37-00-04b, Guidelines for Agents or Advisors acting on behalf of taxpayers (last reviewed September 2026), sections 1, 2 and 14. https://www.revenue.ie/en/tax-professionals/tdm/income-tax-capital-gains-tax-corporation-tax/part-37/37-00-04b.pdf (accessed 11 October 2026). Back
American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.001, paragraphs .01b, .03 and .04, and ET 1.510.010, paragraphs .03 to .05. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026). Back
Chartered Accountants Ireland, Code of Ethics, Parts 1 to 4 (applying from 1 March 2020), introductory note and paragraphs 330.8 A1 to A4, R410.10 and R410.11. https://www.charteredaccountants.ie/docs/default-source/technical-documents/ethics/code-of-ethics---december-2020.pdf?sfvrsn=e828ae7c_3 (accessed 11 October 2026). Back
Irish Taxation Institute, Code of Professional Conduct and Recommended Best Practice Guidelines (version taking effect 15 September 2015), Article 11. https://itiprod2storagegroup.blob.core.windows.net/files/Member%20Resources/ITI-Code-of-Professional-Conduct-effective-201509151.pdf (accessed 11 October 2026). Back
Internal Revenue Service, PTIN requirements for tax return preparers (page last reviewed or updated 16 October 2025). https://www.irs.gov/tax-professionals/ptin-requirements-for-tax-return-preparers (accessed 11 October 2026). Back
Internal Revenue Service, Understanding tax return preparer credentials and qualifications, sections "Unlimited representation rights", "Limited representation rights", "Annual filing season program participants" and "PTIN holders" (page last reviewed or updated 29 January 2026). https://www.irs.gov/tax-professionals/understanding-tax-return-preparer-credentials-and-qualifications (accessed 11 October 2026). Back
Treasury Department and Internal Revenue Service, 26 CFR 1.6109-2, Tax return preparers furnishing identifying numbers for returns or claims for refund and related requirements, paragraphs (a)(1) to (a)(3). https://www.ecfr.gov/current/title-26/section-1.6109-2 (accessed 11 October 2026). Back
Internal Revenue Service, Form 6765, Credit for Increasing Research Activities (Rev. December 2024), pages 1 to 4. https://www.irs.gov/pub/irs-pdf/f6765.pdf (accessed 11 October 2026). Back
Revenue Commissioners, Research and Development Corporation Tax Credit: Pre-filing Notification Form in respect of a claim to be made under section 766C TCA 1997, form and notes. https://www.revenue.ie/en/companies-and-charities/documents/rd-form-766c.pdf (accessed 11 October 2026). Back
Internal Revenue Service, Research credit claims (Section 41) on amended returns frequently asked questions, introduction and questions 4, 7 and 21 (page last reviewed or updated 1 October 2026). https://www.irs.gov/businesses/corporations/research-credit-claims-section-41-on-amended-returns-frequently-asked-questions (accessed 11 October 2026). Back
Office of the Law Revision Counsel, 26 U.S.C. 6662, Imposition of accuracy-related penalty on underpayments, subsections (a), (b), (c) and (d)(1), United States Code 2024 edition published by the Government Publishing Office. https://www.govinfo.gov/content/pkg/USCODE-2024-title26/html/USCODE-2024-title26-subtitleF-chap68-subchapA-partII-sec6662.htm (accessed 11 October 2026). Back
Office of the Law Revision Counsel, 26 U.S.C. 6676, Erroneous claim for refund or credit, subsections (a) and (b), United States Code 2024 edition published by the Government Publishing Office. https://www.govinfo.gov/content/pkg/USCODE-2024-title26/html/USCODE-2024-title26-subtitleF-chap68-subchapB-partI-sec6676.htm (accessed 11 October 2026). Back
Office of the Law Revision Counsel, 26 U.S.C. 6694, Understatement of taxpayer's liability by tax return preparer, subsection (a)(1), United States Code 2024 edition published by the Government Publishing Office. https://www.govinfo.gov/content/pkg/USCODE-2024-title26/html/USCODE-2024-title26-subtitleF-chap68-subchapB-partI-sec6694.htm (accessed 11 October 2026). Back
Revenue Commissioners, Tax and Duty Manual Part 29-02-03 (last updated April 2026), sections 8, 8.6.2 and 8.7. https://www.revenue.ie/en/tax-professionals/tdm/income-tax-capital-gains-tax-corporation-tax/part-29/29-02-03.pdf (accessed 11 October 2026). Back
Revenue Commissioners, Notes for Guidance, Taxes Consolidation Act 1997, Finance Act 2025 edition, Part 47, section 1055. https://www.revenue.ie/en/tax-professionals/documents/notes-for-guidance/tca/part47.pdf (accessed 11 October 2026). Back
Internal Revenue Service, Research credit claims (Section 41) on amended returns frequently asked questions, introduction and questions 3 to 7 and 16 (page last reviewed or updated 1 October 2026). https://www.irs.gov/businesses/corporations/research-credit-claims-section-41-on-amended-returns-frequently-asked-questions (accessed 11 October 2026). Back
Internal Revenue Service, Publication 5, Your Appeal Rights and How to Prepare a Protest if You Disagree (Rev. 4-2021), pages 1 to 6. https://www.irs.gov/pub/irs-pdf/p5.pdf (accessed 11 October 2026). Back
Internal Revenue Service, Research credit claims (Section 41) on amended returns frequently asked questions, introduction and questions 7 and 15 (page last reviewed or updated 1 October 2026). https://www.irs.gov/businesses/corporations/research-credit-claims-section-41-on-amended-returns-frequently-asked-questions (accessed 11 October 2026). Back
Revenue Commissioners, Notes for Guidance, Taxes Consolidation Act 1997, Finance Act 2025 edition, Part 29, section 766, subsection (7). https://www.revenue.ie/en/tax-professionals/documents/notes-for-guidance/tca/part29.pdf (accessed 11 October 2026). Back
Revenue Commissioners, Code of Practice for Revenue Compliance Interventions (effective 1 May 2022), sections 1, 4.6.2 and 4.11.2. https://www.revenue.ie/en/tax-professionals/documents/code-of-practice-revenue-compliance-interventions.pdf (accessed 11 October 2026). Back
Office of the Law Revision Counsel, 26 U.S.C. 6701, Penalties for aiding and abetting understatement of tax liability, subsections (a), (b) and (f)(2), United States Code 2024 edition published by the Government Publishing Office. https://www.govinfo.gov/content/pkg/USCODE-2024-title26/html/USCODE-2024-title26-subtitleF-chap68-subchapB-partI-sec6701.htm (accessed 11 October 2026). Back