Contentious Tax

Our Contentious Tax 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 Contentious Tax 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 on the image below to download our Contentious Tax Brochure.

Contentious Tax



Our Contentious Tax 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. 


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.

Recent TAC Determination Concerning EII

Recent Tax Appeals Commission (TAC) determination concerning the Employment and Investment Incentive (EII) scheme.

Ireland Supports Mechanisms to Resolve Double Taxation Disputes Between Member States

To strengthen the mechanisms available to resolve double taxation disputes between Member States, the EU introduced the Dispute Resolution Mechanism Directive ((EU) 2017/1852) (DRM) which was transposed into Irish law and took effect from 1 July 2019. The European Union (Tax Dispute Resolution Mechanisms) (Amendment) Regulations 2020 were signed by the Minister for Finance on 18 December 2020 to ensure that full effect is given to the mechanisms available under the DRM

Finance Bill 2020 Proposals – Improvements to the Practice & Procedure of the Tax Appeals Commission

Budget 2021 was announced on 13 October 2020. In addition to the budget, the Finance Bill 2020 proposes certain changes to the practices and procedures of the Tax Appeals Commission.

What To Expect When You Are Legitimately Expecting

On 3 June 2020 Perrigo opened its case in the High Court in a bid to quash one of the most contentious tax bills levied on a company in Ireland. This article considers the legal concept of legitimate expectation and the thresholds that Perrigo may have to meet to succeed in its case to have the tax bill reversed.

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  • 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 Shane Wallace recently handled various real estate tax structuring and transfer pricing issues. 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


    Sonya Manzor

    • 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

    Ted McGrath

    • According to clients, Ted McGrath offers "practical, concise, sound and logical commercial advice," with another client stating they "turn first to Martin Phelan and Ted McGrath at William Fry." 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

    Key Contacts

    Brian Duffy Partner

    Fergus Doorly Partner

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