Matheson LLP is highly active in complex competition matters, frequently advising on Phase II merger cases, high-value acquisitions, and investigations by the CCPC. The team is led by Niall Collins, who has extensive experience advising both Irish and multinational clients on all aspects of Irish and EU competition law. Kate McKenna is a key figure for her work on mergers, acquisitions, and competition litigation, while Calum Warren is recognised for advising clients on emerging regulatory frameworks, including Ireland’s new foreign direct investment screening regime.
Legal 500 Editorial commentary
Accolades
Client satisfaction: Lawyer & team quality
Client satisfaction: Sector knowledge
Testimonials
Collated independently by Legal 500 research team.
- ‘Calum Warren will walk through walls for his clients and has deep knowledge, leveraging specialist experience interfacing with enforcers in London, Dublin and Brussels.'
- ‘Very strong team with excellent technical knowledge and a commercial and pragmatic approach.’
- ‘Very strong team technically. Provides responsive and commercial support. First choice in Ireland.’
- ‘Niall Collins is the first port of call for all Irish queries. He is very experienced and provides great insight - commercial, pragmatic and actionable advice.'
- ‘The team is highly responsive and knowledgeable, with unmatched experience in cutting-edge and high-stakes competition mandates.’
- In-depth experience of competition law.
- Matheson combines Irish regulatory depth with true cross-border execution. The team translates fast-moving Irish/EU rules into practical, business-ready advice. Sector fluency—particularly in technology, life sciences, and financial services—means they anticipate issues early and clear them efficiently.
- Great demonstrable subject matter expertise. Quick turnaround. Understood the ask and delivered.
- The Matheson team stands out for crisp, business-first advice, speed without sacrificing accuracy, and true cross-border fluency. Calum Warren, in particular, blends sharp technical analysis with practical, solutions-oriented judgment; he’s calm under pressure, anticipates regulator concerns, and drives matters forward with clear, action-ready drafting. I’ve also valued his strategic oversight and ability to simplify complex competition issues, as well as his reliability and responsiveness on short deadlines. What differentiates him from competitors is consistency: he does not just identify risk—he quantifies it, proposes workable paths, and executes with empathy and integrity.
- Kate McKenna is clever, responsive, and able to understand the context, with an in-depth knowledge of state aid law.
Key clients
- Equinix Windward Management / Emerald Investments Arrow Global / Mars Capital Getty Images Yellow Com Lyca Mobile ICG plc Cellnex Telecom Oracle Aon Kerry Group Credit Union Mortgage Services Ireland Winthrop Technologies CMA CGM Brookfield Corporation Tirlán Co-operative Society Mediahuis NV AXA S.A. Meta Bauer Media Group Blackrock Health CLdN Gilead Grain Management Insurance Ireland Hayden AI Le Creuset MTM Packaging Smurfit Kappa Group Ticketmaster Bank of Ireland Three Ireland (and its parent CK Hutchison) Parma Investments Limited, and its parent Goodman Group Daily Mail / DMGT plc Discovery Enterprise Ireland ASL Aviation Brokers Ireland Orpea S.A Ornua Speed Fibre Group (enet, Airspeed and Magnet) & its parent AMP Capital SSE Irish Distillers and its parent, Pernod Ricard AIB An Post Fexco Abtran Aramark Bord Na Mona Boskalis College Proteins Commercial Mushrooms Producers Co-Operative Society (CMP) Carr Communications Chapel Gate Commscope Discovery Department for Energy daa plc Disney Energia FitBit Irving Oil / Top Oil JPI Media plc Microsoft Monument Re Monaghan Mushrooms Newsbrands Nicholl (Fuel Oils) Ltd Nomad Foods Oaktree Opel Post Office Limited Saint Gobain Sky Ireland Sport Ireland TINE TripActions Irish Life Waystone (Ireland) Ltd Iveco SpA Linnaeus Veterinary Group Vermilion Energy Inc Vodafone Ireland Ltd Worldwide Flight Services (WFS) Carne Global Financial Services Ltd Royal Bank of Canada Supersapiens Shares.io Alibaba.com Aer-Rianta International cpt Fresenius Medical Care (Ireland) Ltd Wellster Healthtech Group GmbH Virgin Media Macquarie Group Limited
Work highlights
Acted for Cellnex Telecom S.A. on the sale of its Irish business to Phoenix Tower International.
Advising Speed Fibre Group on its acquisition of BT’s wholesale and enterprise business unit in Ireland.
Acting for Oracle on the application of the new EU Foreign Subsidies Regulation.
Lawyers
Hall of Fame
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Leading partners
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Next Generation Partners
Junior partners with significant recognition from clients and peers in the market and key roles on multiple matters.
Practice head
Niall Collins
Other key lawyers
Kate McKenna; Calum Warren