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Professional body rules by country

What the main accounting and tax professional codes in the five countries covered on this site say about contingent fees for tax work, and who those codes bind.

  • Rules as at
On this page
  1. Notes
  2. Sources

Professional bodies set their own rules on how members may charge for tax work, separately from statute. This page compares the main codes reviewed on each country page: which codes they are, who they bind, and what they say about contingent fees for tax return or claim work. A code binds the members of the body that issues it, so an adviser who belongs to no body is outside it. Each cell cites the same source as the matching country page, and the notes below give the detail the table leaves out. The page describes the rules only and makes no recommendation.

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

Country Codes reviewed Who is bound Contingent fees for tax work
United States AICPA Code of Professional Conduct, Contingent Fees Rule (ET 1.510)1Source 1American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.001, Contingent Fees Rule, paragraphs .01, .03 and .04. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026). AICPA members in public practice2Source 2American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 0.400, Definitions, paragraph .33 (Member). https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026). Not permitted for preparing an original or amended return or refund claim, unless the fee is based on the findings of a governmental agency as the Code defines1Source 1American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.001, Contingent Fees Rule, paragraphs .01, .03 and .04. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026).3Source 3American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.010, Tax Matters, paragraphs .01 to .05. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026).
United Kingdom PCRT; CIOT and ATT Professional Rules and Practice Guidelines; ICAEW Code of Ethics 20264Source 4AAT, ACCA, ATT, CIOT, ICAEW, ICAS and STEP, Professional Conduct in Relation to Taxation (effective 1 January 2026, published 1 October 2025), Foreword and paragraphs 1.2, 1.7, 1.10, 1.11, 2.2, 2.4, 2.5, 2.9 and 2.13. https://www.icaew.com/-/media/corporate/files/technical/tax/pcrt/pcrt-effective-1-january-2026.ashx (accessed 11 October 2026).5Source 5Chartered Institute of Taxation and Association of Taxation Technicians, Professional Rules and Practice Guidelines (effective 9 November 2018, updated 1 January 2021), paragraphs 8.1.1, 8.1.2, 8.2.1 to 8.2.5 and 8.3.1. https://www.att.org.uk/sites/default/files/PRPG%20%28Update%201.1.2021%29%20-%20Final.pdf (accessed 11 October 2026). Current edition confirmed on the CIOT page https://www.tax.org.uk/professional-rules-and-practice-guidelines (accessed 11 October 2026).6Source 6ICAEW, ICAEW Code of Ethics 2026 (applies from 1 July 2026), paragraph 1.1, section 330, paragraphs R330.4, R330.5, R330.7 and R330.4B.1 and the paragraphs headed "Contingent Fees", and section 410, paragraphs R410.9 and R410.10. https://www.icaew.com/-/media/corporate/files/technical/ethics/code-of-ethics/icaew-code-of-ethics-2026-revisions-highlighted.ashx (accessed 11 October 2026). Members of the issuing bodies4Source 4AAT, ACCA, ATT, CIOT, ICAEW, ICAS and STEP, Professional Conduct in Relation to Taxation (effective 1 January 2026, published 1 October 2025), Foreword and paragraphs 1.2, 1.7, 1.10, 1.11, 2.2, 2.4, 2.5, 2.9 and 2.13. https://www.icaew.com/-/media/corporate/files/technical/tax/pcrt/pcrt-effective-1-january-2026.ashx (accessed 11 October 2026).5Source 5Chartered Institute of Taxation and Association of Taxation Technicians, Professional Rules and Practice Guidelines (effective 9 November 2018, updated 1 January 2021), paragraphs 8.1.1, 8.1.2, 8.2.1 to 8.2.5 and 8.3.1. https://www.att.org.uk/sites/default/files/PRPG%20%28Update%201.1.2021%29%20-%20Final.pdf (accessed 11 October 2026). Current edition confirmed on the CIOT page https://www.tax.org.uk/professional-rules-and-practice-guidelines (accessed 11 October 2026).6Source 6ICAEW, ICAEW Code of Ethics 2026 (applies from 1 July 2026), paragraph 1.1, section 330, paragraphs R330.4, R330.5, R330.7 and R330.4B.1 and the paragraphs headed "Contingent Fees", and section 410, paragraphs R410.9 and R410.10. https://www.icaew.com/-/media/corporate/files/technical/ethics/code-of-ethics/icaew-code-of-ethics-2026-revisions-highlighted.ashx (accessed 11 October 2026). No specific provision in PCRT; the PRPG and the ICAEW Code allow them with care or safeguards for objectivity4Source 4AAT, ACCA, ATT, CIOT, ICAEW, ICAS and STEP, Professional Conduct in Relation to Taxation (effective 1 January 2026, published 1 October 2025), Foreword and paragraphs 1.2, 1.7, 1.10, 1.11, 2.2, 2.4, 2.5, 2.9 and 2.13. https://www.icaew.com/-/media/corporate/files/technical/tax/pcrt/pcrt-effective-1-january-2026.ashx (accessed 11 October 2026).5Source 5Chartered Institute of Taxation and Association of Taxation Technicians, Professional Rules and Practice Guidelines (effective 9 November 2018, updated 1 January 2021), paragraphs 8.1.1, 8.1.2, 8.2.1 to 8.2.5 and 8.3.1. https://www.att.org.uk/sites/default/files/PRPG%20%28Update%201.1.2021%29%20-%20Final.pdf (accessed 11 October 2026). Current edition confirmed on the CIOT page https://www.tax.org.uk/professional-rules-and-practice-guidelines (accessed 11 October 2026).6Source 6ICAEW, ICAEW Code of Ethics 2026 (applies from 1 July 2026), paragraph 1.1, section 330, paragraphs R330.4, R330.5, R330.7 and R330.4B.1 and the paragraphs headed "Contingent Fees", and section 410, paragraphs R410.9 and R410.10. https://www.icaew.com/-/media/corporate/files/technical/ethics/code-of-ethics/icaew-code-of-ethics-2026-revisions-highlighted.ashx (accessed 11 October 2026).
Ireland Chartered Accountants Ireland Code of Ethics; Irish Tax Institute Code of Professional Conduct7Source 7Chartered Accountants Ireland, Code of Ethics, Parts 1 to 4 (applying from 1 March 2020), introductory note, paragraphs R330.7, 330.8 A1 to A4, R410.10, R410.11, 604.3 A1, 604.4 A1, R905.7, R905.8 and the Glossary entry "Contingent fee". https://www.charteredaccountants.ie/docs/default-source/technical-documents/ethics/code-of-ethics---december-2020.pdf?sfvrsn=e828ae7c_3 (accessed 11 October 2026).8Source 8Irish Tax Institute, Code of Professional Conduct and Recommended Best Practice Guidelines (document headed Irish Taxation Institute; version taking effect 15 September 2015), Introduction, Amendment of Code of Conduct, Article 11 and paragraphs 11.1.2, 11.1.6 and 11.1.8. Linked from the Irish Tax Institute's professional standards page, https://taxinstitute.ie/about-us/professional-standards/. https://itiprod2storagegroup.blob.core.windows.net/files/Member%20Resources/ITI-Code-of-Professional-Conduct-effective-201509151.pdf (accessed 11 October 2026). Members only; membership is not a condition of acting as a tax agent9Source 9Revenue Commissioners, Tax and Duty Manual Part 37-00-04b, Guidelines for Agents or Advisors acting on behalf of taxpayers (last reviewed September 2026), section 1. 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). Chartered Accountants Ireland: a possible self-interest threat to be evaluated; Irish Tax Institute: no specific rule7Source 7Chartered Accountants Ireland, Code of Ethics, Parts 1 to 4 (applying from 1 March 2020), introductory note, paragraphs R330.7, 330.8 A1 to A4, R410.10, R410.11, 604.3 A1, 604.4 A1, R905.7, R905.8 and the Glossary entry "Contingent fee". https://www.charteredaccountants.ie/docs/default-source/technical-documents/ethics/code-of-ethics---december-2020.pdf?sfvrsn=e828ae7c_3 (accessed 11 October 2026).8Source 8Irish Tax Institute, Code of Professional Conduct and Recommended Best Practice Guidelines (document headed Irish Taxation Institute; version taking effect 15 September 2015), Introduction, Amendment of Code of Conduct, Article 11 and paragraphs 11.1.2, 11.1.6 and 11.1.8. Linked from the Irish Tax Institute's professional standards page, https://taxinstitute.ie/about-us/professional-standards/. https://itiprod2storagegroup.blob.core.windows.net/files/Member%20Resources/ITI-Code-of-Professional-Conduct-effective-201509151.pdf (accessed 11 October 2026).
Canada CPA Code of Professional Conduct as published by CPA Ontario, Rule 21510Source 10Chartered Professional Accountants of Ontario, CPA Code of Professional Conduct, cover page, Definitions ("contingent fee"), and Rule 215, Contingent fees (Rules 215.1 and 215.2 and Guidance paragraphs 1 to 7). https://assets.cpaontario.ca/members/regulations-guidance/pdfs/CPA-Ontario-Code-of-professional-conduct.pdf (accessed 11 October 2026). Members of CPA Ontario and firms10Source 10Chartered Professional Accountants of Ontario, CPA Code of Professional Conduct, cover page, Definitions ("contingent fee"), and Rule 215, Contingent fees (Rules 215.1 and 215.2 and Guidance paragraphs 1 to 7). https://assets.cpaontario.ca/members/regulations-guidance/pdfs/CPA-Ontario-Code-of-professional-conduct.pdf (accessed 11 October 2026). Barred for preparing an income tax return; other services allowed with the client's written agreement to the fee basis10Source 10Chartered Professional Accountants of Ontario, CPA Code of Professional Conduct, cover page, Definitions ("contingent fee"), and Rule 215, Contingent fees (Rules 215.1 and 215.2 and Guidance paragraphs 1 to 7). https://assets.cpaontario.ca/members/regulations-guidance/pdfs/CPA-Ontario-Code-of-professional-conduct.pdf (accessed 11 October 2026).
Singapore ISCA Ethics Pronouncement 100; SCTP Code of Ethics and Professional Conduct11Source 11Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraph SG010.1. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).12Source 12Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 2.2 and 2.8. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026). Members of ISCA or SCTP11Source 11Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraph SG010.1. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).12Source 12Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 2.2 and 2.8. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026). ISCA: allowed for non-assurance services, subject to the conceptual framework; SCTP: the Code does not use the term13Source 13Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraphs 330.4 A1 to 330.4 A4. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).14Source 14Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 3.6 and 3.10. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026).

Notes

United States. Treasury stated in its December 2024 proposal that many state accountancy board rules also prohibit contingent fees for preparing an original or amended return or refund claim.15Source 15Treasury Department and Internal Revenue Service, Regulations Governing Practice Before the Internal Revenue Service, notice of proposed rulemaking, 89 FR 104915 (26 December 2024), Explanation of Provisions part B and accompanying notes. https://www.federalregister.gov/documents/2024/12/26/2024-29371/regulations-governing-practice-before-the-internal-revenue-service (accessed 11 October 2026). The Code's examples permit a contingent fee for representing a client in a revenue agent's examination, but not for an amended return claiming a refund because a valid deduction was inadvertently omitted.3Source 3American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.010, Tax Matters, paragraphs .01 to .05. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026). The IRS states that a preparer with no professional credential who does not take part in the Annual Filing Season Program has no authority to represent clients before it.16Source 16Internal Revenue Service, Understanding tax return preparer credentials and qualifications, sections "Unlimited representation rights" 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).

United Kingdom. HMRC estimates that around 65 percent of agents are members of professional bodies.17Source 17HM Revenue and Customs, The HMRC standard for agents (updated 9 February 2026), sections 2, 2.1, 2.2 and 3.2. https://www.gov.uk/government/publications/hmrc-the-standard-for-agents/the-hmrc-standard-for-agents (accessed 11 October 2026). The PRPG say contingent fees can carry increased risks and remind members that a contingent fee may be considered a premium fee under the rules on disclosure of tax avoidance schemes.5Source 5Chartered Institute of Taxation and Association of Taxation Technicians, Professional Rules and Practice Guidelines (effective 9 November 2018, updated 1 January 2021), paragraphs 8.1.1, 8.1.2, 8.2.1 to 8.2.5 and 8.3.1. https://www.att.org.uk/sites/default/files/PRPG%20%28Update%201.1.2021%29%20-%20Final.pdf (accessed 11 October 2026). Current edition confirmed on the CIOT page https://www.tax.org.uk/professional-rules-and-practice-guidelines (accessed 11 October 2026). The ICAEW Code prohibits contingent fees for audit engagements.6Source 6ICAEW, ICAEW Code of Ethics 2026 (applies from 1 July 2026), paragraph 1.1, section 330, paragraphs R330.4, R330.5, R330.7 and R330.4B.1 and the paragraphs headed "Contingent Fees", and section 410, paragraphs R410.9 and R410.10. https://www.icaew.com/-/media/corporate/files/technical/ethics/code-of-ethics/icaew-code-of-ethics-2026-revisions-highlighted.ashx (accessed 11 October 2026).

Ireland. Chartered Accountants Ireland prohibits contingent fees for audit engagements and in defined cases for non-assurance services to audit clients.7Source 7Chartered Accountants Ireland, Code of Ethics, Parts 1 to 4 (applying from 1 March 2020), introductory note, paragraphs R330.7, 330.8 A1 to A4, R410.10, R410.11, 604.3 A1, 604.4 A1, R905.7, R905.8 and the Glossary entry "Contingent fee". https://www.charteredaccountants.ie/docs/default-source/technical-documents/ethics/code-of-ethics---december-2020.pdf?sfvrsn=e828ae7c_3 (accessed 11 October 2026). Under the Irish Tax Institute code, members set their own fee method, and the code says members should make sure the engagement letter sets out an estimate of the fees and the method of calculating them.8Source 8Irish Tax Institute, Code of Professional Conduct and Recommended Best Practice Guidelines (document headed Irish Taxation Institute; version taking effect 15 September 2015), Introduction, Amendment of Code of Conduct, Article 11 and paragraphs 11.1.2, 11.1.6 and 11.1.8. Linked from the Irish Tax Institute's professional standards page, https://taxinstitute.ie/about-us/professional-standards/. https://itiprod2storagegroup.blob.core.windows.net/files/Member%20Resources/ITI-Code-of-Professional-Conduct-effective-201509151.pdf (accessed 11 October 2026).

Canada. Rule 215 and its guidance do not mention SR&ED claims or Form T661, so whether preparing Form T661 counts as preparing an income tax return under the rule is not addressed in the sources reviewed.10Source 10Chartered Professional Accountants of Ontario, CPA Code of Professional Conduct, cover page, Definitions ("contingent fee"), and Rule 215, Contingent fees (Rules 215.1 and 215.2 and Guidance paragraphs 1 to 7). https://assets.cpaontario.ca/members/regulations-guidance/pdfs/CPA-Ontario-Code-of-professional-conduct.pdf (accessed 11 October 2026). The Income Tax Act defines an SR&ED claim preparer by reference to accepting consideration, not membership of a professional body.18Source 18Government of Canada, Income Tax Act, RSC 1985, c 1 (5th Supp), subsections 162(5.1), (5.2) and (5.3). https://laws-lois.justice.gc.ca/eng/acts/I-3.3/section-162.html (accessed 11 October 2026). The Quebec code and the other provincial CPA codes were not reviewed on the country page.

Singapore. ISCA prohibits contingent fees for audit engagements.19Source 19Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraphs R410.9 and R410.10. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026). The SCTP Code requires disclosure of third-party commissions and recommends that an engagement letter set out the basis on which fees are charged.14Source 14Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 3.6 and 3.10. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026).20Source 20Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraph 8.18. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026). Neither code refers specifically to R&D deductions or the Enterprise Innovation Scheme.11Source 11Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraph SG010.1. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).12Source 12Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 2.2 and 2.8. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026).

Sources

  1. American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.001, Contingent Fees Rule, paragraphs .01, .03 and .04. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026).   Back
  2. American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 0.400, Definitions, paragraph .33 (Member). https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026).  Back
  3. American Institute of CPAs, Code of Professional Conduct (updated for all official releases through September 2026), ET 1.510.010, Tax Matters, paragraphs .01 to .05. https://pub.aicpa.org/codeofconduct/ethicsresources/et-cod.pdf (accessed 11 October 2026).   Back
  4. AAT, ACCA, ATT, CIOT, ICAEW, ICAS and STEP, Professional Conduct in Relation to Taxation (effective 1 January 2026, published 1 October 2025), Foreword and paragraphs 1.2, 1.7, 1.10, 1.11, 2.2, 2.4, 2.5, 2.9 and 2.13. https://www.icaew.com/-/media/corporate/files/technical/tax/pcrt/pcrt-effective-1-january-2026.ashx (accessed 11 October 2026).    Back
  5. Chartered Institute of Taxation and Association of Taxation Technicians, Professional Rules and Practice Guidelines (effective 9 November 2018, updated 1 January 2021), paragraphs 8.1.1, 8.1.2, 8.2.1 to 8.2.5 and 8.3.1. https://www.att.org.uk/sites/default/files/PRPG%20%28Update%201.1.2021%29%20-%20Final.pdf (accessed 11 October 2026). Current edition confirmed on the CIOT page https://www.tax.org.uk/professional-rules-and-practice-guidelines (accessed 11 October 2026).     Back
  6. ICAEW, ICAEW Code of Ethics 2026 (applies from 1 July 2026), paragraph 1.1, section 330, paragraphs R330.4, R330.5, R330.7 and R330.4B.1 and the paragraphs headed "Contingent Fees", and section 410, paragraphs R410.9 and R410.10. https://www.icaew.com/-/media/corporate/files/technical/ethics/code-of-ethics/icaew-code-of-ethics-2026-revisions-highlighted.ashx (accessed 11 October 2026).     Back
  7. Chartered Accountants Ireland, Code of Ethics, Parts 1 to 4 (applying from 1 March 2020), introductory note, paragraphs R330.7, 330.8 A1 to A4, R410.10, R410.11, 604.3 A1, 604.4 A1, R905.7, R905.8 and the Glossary entry "Contingent fee". https://www.charteredaccountants.ie/docs/default-source/technical-documents/ethics/code-of-ethics---december-2020.pdf?sfvrsn=e828ae7c_3 (accessed 11 October 2026).    Back
  8. Irish Tax Institute, Code of Professional Conduct and Recommended Best Practice Guidelines (document headed Irish Taxation Institute; version taking effect 15 September 2015), Introduction, Amendment of Code of Conduct, Article 11 and paragraphs 11.1.2, 11.1.6 and 11.1.8. Linked from the Irish Tax Institute's professional standards page, https://taxinstitute.ie/about-us/professional-standards/. https://itiprod2storagegroup.blob.core.windows.net/files/Member%20Resources/ITI-Code-of-Professional-Conduct-effective-201509151.pdf (accessed 11 October 2026).    Back
  9. Revenue Commissioners, Tax and Duty Manual Part 37-00-04b, Guidelines for Agents or Advisors acting on behalf of taxpayers (last reviewed September 2026), section 1. 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
  10. Chartered Professional Accountants of Ontario, CPA Code of Professional Conduct, cover page, Definitions ("contingent fee"), and Rule 215, Contingent fees (Rules 215.1 and 215.2 and Guidance paragraphs 1 to 7). https://assets.cpaontario.ca/members/regulations-guidance/pdfs/CPA-Ontario-Code-of-professional-conduct.pdf (accessed 11 October 2026).     Back
  11. Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraph SG010.1. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).    Back
  12. Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 2.2 and 2.8. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026).    Back
  13. Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraphs 330.4 A1 to 330.4 A4. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).  Back
  14. Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraphs 3.6 and 3.10. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026).   Back
  15. Treasury Department and Internal Revenue Service, Regulations Governing Practice Before the Internal Revenue Service, notice of proposed rulemaking, 89 FR 104915 (26 December 2024), Explanation of Provisions part B and accompanying notes. https://www.federalregister.gov/documents/2024/12/26/2024-29371/regulations-governing-practice-before-the-internal-revenue-service (accessed 11 October 2026).  Back
  16. Internal Revenue Service, Understanding tax return preparer credentials and qualifications, sections "Unlimited representation rights" 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
  17. HM Revenue and Customs, The HMRC standard for agents (updated 9 February 2026), sections 2, 2.1, 2.2 and 3.2. https://www.gov.uk/government/publications/hmrc-the-standard-for-agents/the-hmrc-standard-for-agents (accessed 11 October 2026).  Back
  18. Government of Canada, Income Tax Act, RSC 1985, c 1 (5th Supp), subsections 162(5.1), (5.2) and (5.3). https://laws-lois.justice.gc.ca/eng/acts/I-3.3/section-162.html (accessed 11 October 2026).  Back
  19. Institute of Singapore Chartered Accountants, Ethics Pronouncement 100: Code of Professional Conduct and Ethics (effective 1 July 2025), paragraphs R410.9 and R410.10. https://isca.org.sg/docs/default-source/ep-100/eps-100/code-of-ethics-for-isca-ep-100-(effective-1-jul-25).pdf (accessed 11 October 2026).  Back
  20. Singapore Chartered Tax Professionals, Code of Ethics and Professional Conduct (effective 1 September 2026), paragraph 8.18. https://www.sctp.org.sg/Ethics-Code.pdf (accessed 11 October 2026).  Back