Tax Litigation & Disputes

Our Tax Litigation & Disputes team consists of tax advisors, chartered accountants, barristers and solicitors who work extensively in the tax controversy area. We act for individuals and corporates and assist our clients in resolving contentious tax matters before any court proceedings commence.

Our Tax Litigation & Disputes service offering includes:

  • confidential reviews of tax filing positions taken and legacy tax matters;
  • advising on voluntary tax disclosures and tax settlements with tax authorities;
  • advocating on behalf of and representing clients at Tax Appeals Commission and High Court levels;
  • provision of expert witness tax reports;
  • tax risk management; 
  • tax warranty and tax indemnity claims;
  • assisting clients prior to and during tax investigations and audits; and
  • assisting with mutual assistance procedures (MAPs).

We concentrate on tax law and therefore have no accounting, audit or attest issues. We can therefore focus entirely on advising and supporting clients to adopt best practices, become more cost-efficient and reduce the burden that tax issues bring.

Click here on the image below to download our Tax Litigation and Disputes Group Brochure.

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Our Tax Litigation and Disputes team is composed of tax advisors (AITI/CTA), chartered accountants, barristers and solicitors. The team has gained considerable experience in dealing with Revenue audits and investigations, MAPs, and settlement negotiations with tax authorities. We have also acted as expert witnesses for taxpayers and foreign tax authorities in complex tax appeal cases.

Concerning tax litigation we have, in the past, advocated on behalf of and represented clients at Appeal Commissioner/Tax Appeals Commission, Circuit Court and High Court levels on matters relating to, inter alia, DIRT, income tax, capital gains tax, stamp duty, VRT, corporation tax, VAT and international tax matters. 


Multinationals and Intercompany Debt: The Tax Implications of Unwinding Intercompany Debt

A €25m tax battle before the Tax Appeals Commission clarifies the corporation tax treatment when intercompany debt is unwound.

Revenue's Annual Report 2021

In May 2022, Revenue published its annual report for 2021. The Report reviews how Revenue is performing against the backdrop of a changing trading environment between Ireland and the United Kingdom, and the continued economic and social disruptions caused by the Covid-19 pandemic.

The Tax Appeals Commission Annual Report 2021

On 25 April 2022, the Tax Appeals Commission published its annual report for 2021 (Report); the Report includes a wide range of metrics and indicators to demonstrate how the TAC is performing in its role of administering tax appeals. In this article we consider some of the key statistics from the Report.

What You Need to Know About the New Code of Practice for Revenue Compliance Interventions

A new Code of Practice for Revenue Compliance Interventions was recently published. From 1 May 2022, the Code of Practice will significantly change interactions between Revenue and taxpayers.

Stamp Duty Battle: Abbvie Wins Appeal Against €587m Irish Stamp Duty

A recent decision of the Tax Appeals Commission will peak the interests of Pharma, Healthcare and MedTech companies considering M&A transactions in the Irish market.

View all


  • "The team is professional, well informed and forward thinking. Very responsive, with an excellent range of tax knowledge both locally and internationally." Legal 500 2020, Tax 
  • William Fry's Tax team have been described as "professional, well informed and forward thinking" as well as being a "responsive and partner-led tax practice issuing practical advice." One client notes that the team has an abundance of "knowledge, experience, professionalism and the ability to apply lateral thinking and multi solutions." Another client adds that they have "an excellent range of tax knowledge both locally and internationally." They are very "responsive and helpful, and we fully trust the advice that we receive."  Legal 500 2020
  • There's a real broadness, a client states "You can talk to one person who has a legal, tax and international perspective all in one".  Other sources appreciate the client-centric service provided by team members: "We've got a great relationship with the team and we find them to be very effective. They really demonstrate their commitment to client service". Chamber Europe 2019  
  • "William Fry's commitment to client service is excellent", says one source, who also praises "their real breadth of knowledge and willingness to allocate the people required when there is a need for a quick turnaround." Another reports that the "technical depth, exposure and experience of the senior team set them apart." Chambers Europe 2018
  • "Sources assert that "from a technical perspective they are clear and direct." Interviewees also value the team's "responsiveness to client needs and commercial awareness." Chambers Europe 2017
  • William Fry’s practice includes Sonya Manzor, who ‘devises well-thought-out tax strategies’ for clients such as King Digital Entertainment. International tax specialist. Legal 500 EMEA 2017
  • "The firm is very responsive and has great resources, including access to a global network of tax advisers, which benefits us internationally and is a fantastic asset. The firm's ability to provide both legal and tax advice really ensures everything fits together.Chambers Europe 2016


Paul Convery

  • "Paul Convery has good nerve, relates easily to international clients, and has an excellent eye for what really are the key issues in complex cases." Legal 500 2021

    Sonya Manzor

    • "Sonya Manzor leads a very strong team at William Fry. I have worked with Sonya for several years and have always found her and the members of the wider William Fry team to be excellent. Sonya and her team provide superb client service to us." Legal 500 2021, Tax 
    • According to clients, Manzor is "technically very good, commercial in her approach and gives excellent client support." Chambers Europe 2020 
    • "I really admire the way that Manzor is able to review advice and drill into the key technical points and make very sensible, constructive comments on the tax issues," enthuses one highly impressed interviewee. Chambers Europe 2019
    • The "outstanding" Sonya Manzor is a key name in the corporate tax space. Legal 500 2018 
    • Clients describe her as "a very talented individual and creative thinker." She assisted with the sale of Phillips 66's interests in the Whitegate Oil Refinery. Chambers Europe 2018
    • Sonya Manzor is "well renowned for her technical expertise in a broad spectrum of tax matters, including inward investment, corporate reorganisations and M&A transactions". Chambers Europe 2017
    • Sonya Manzor is the firm's most prominent corporate tax lawyer, coming recognised for her "tremendous knowledge and experience. She understands direct and indirect tax in Ireland, the EU and the US. She is instrumental in coming up with creative ideas to get around the problems we face."  Chambers Europe 2016

    Brian Duffy

    • "Brian Duffy is commercial and responsive." Legal 500 2020, Tax

    Fergus Doorly

    • "Fergus Doorly offers clear and contextualised advice to help clients navigate complex matters of Irish law. He is friendly, unflappable and works collaboratively with co-counsel from other jurisdictions." Chambers Global 2021

    Ted McGrath

    • According to clients, Ted McGrath offers "practical, concise, sound and logical commercial advice."  Chambers Europe 2020 
    • Ted McGrath debuts in the rankings this year on the back of strong client endorsements. "McGrath gives very pragmatic and direct advice," reports one pleased client, adding: "He can weigh up the commercial aspects of the deal." Chambers Europe 2019

    Declan Lavelle

    • "Declan Lavelle is top drawer, maintaining a friendly approach coupled with advice of the highest quality." Legal 500 2020, Tax

    Rachel Fox

    • "Rachel delivers practical legal advice, provided in a timely fashion and with the highest attention to quality." Legal 500 2021, Tax

    Key Contacts

    Brian Duffy Partner

    Fergus Doorly Partner