Patrick is a partner in the Competition and Regulated Markets Group. His practice covers the full range of EU and Irish competition law.

Patrick advises clients on a wide range of competition and regulatory matters, including including merger control, investigations, State aid, competition law aspects of agreements, implementation of compliance programmes, and competition litigation. Prior to joining Arthur Cox in 2016, Patrick worked in the London and Brussels offices of Slaughter and May. Patrick is co-author of the Ireland chapters of the International Comparative Legal Guide to Competition Litigation and Merger Control, and in 2017 was named as one of the future leaders in competition law by Who’s Who Legal.

Relevant Experience

  • Advising AIB and First Data Corporation on the EU merger control aspects of their joint acquisition of Payzone Ireland
  • Advising Mediahuis NV in securing approval from the CCPC and the Minister for Communication for its €145.6 million acquisition of Independent News & Media plc
  • Advising Cognziant Technology Solutions Corporation on the Irish merger control aspects of its acquisition of Zenith Technologies
  • Advising LacPatrick Cooperative Society on its merger with Lakeland Dairies
  • Advising eir on the EU and Irish merger control and regulatory aspects of its acquisition by Xavier Niel
  • Advising undertakings in the motor insurance sector in connection with the ongoing investigations by the CCPC and the European Commission
  • Advising Accenture on the Irish merger control aspects of its acquisition of the Rothco Group
  • Advising Greenergy International on the EU merger control aspects of its acquisition of Inver Energy
  • Advising Volvo Trucks and Renault Trucks on its defence of follow-on damages actions in the Irish High Court arising from the European Commission’s decision in the Trucks cartel
  • Advising CRH plc in relation to the CCPC’s investigation in to the bagged cement sector in Ireland, as well as advising CRH in relation to its successful defence of the CCPC’s Supreme Court appeal against the decision of the High Court concerning a dawn raid conducted in May 2015


“Patrick Horan has immense technical knowledge in the area of Competition law and he is an absolute pleasure to work with.”

 The Legal 500: Europe, Middle East & Africa, 2022

“Patrick Horan is an excellent lawyer who provides competition telco advice to us. This is an extremely specialised and complex area and Patrick provides a clear, risk-based analysis in a easily digestible manner.”

The Legal 500: Europe, Middle East & Africa, 2022

“Patrick Horan is an expert in competition law; he combines that expertise with a depth of commercial awareness and experience, which is extremely valuable to his clients.”

Chambers Europe: Europe’s Leading Lawyers for Business, 2022

“Patrick Horan is tremendous to work with and the best competition lawyer we have worked with across Europe. His grasp of niche economic business matters with the law made us feel very comfortable.”

The Legal 500: Europe, Middle East & Africa, 2020

Education & Qualifications

  • LLM, 2007, Trinity College Dublin
  • LLB, 2006, Trinity College Dublin
  • Admitted as a solicitor in Ireland, 2016
  • Admitted as a solicitor in England & Wales, 2010
  • Member of the Law Society of Ireland
  • Member of the Law Society of England & Wales
  • Member of the Irish Society of European Law