Expertise
Calum Warren is a partner in the Competition and Regulation Group in Dublin. Prior to joining Matheson, Calum worked at leading international law firms in Brussels and London.
Calum is a leading advisor on all aspects of Irish and EU competition and regulatory law, including M&A regulatory clearances, competition compliance, investigations and litigation, sectoral regulation and general EU regulatory law, public procurement and State aid. Calum is also at the forefront in advising clients on newer regulatory regimes including the new Irish foreign direct investment (FDI) screening regime, the EU Foreign Subsidies Regulation (FSR) regime and new EU digital regulations including the Digital Markets Act and the Digital Services Act.
His experience spans a range of sectors including financial services, technology, media and telecommunications (TMT), agri-business, energy, manufacturing, healthcare, food & beverages and transport.
Calum is consistently ranked in the leading legal directories including as a ‘Next Generation Partner’ by Legal500, and has received strong praise for his technical expertise and commercial and solution-focused approach.
Calum contributes articles to leading international legal publications, is regularly consulted and quoted as an industry expert and speaks regularly on Irish and EU competition and regulatory issues.
Calum is member of the board of the Irish Society of European Law, serves as a non-government advisor to the Irish competition regulator (CCPC) and is currently Vice-Chair of Compliance & Ethics Committee of the American Bar Association’s (ABA) Antitrust Law Section – the only Irish competition lawyer and one of a small number of EU competition lawyers holding such position in the ABA’s Antitrust Law Section.
Merger Control / FDI Screening / EU Foreign Subsidies Regulation
- Advising Smurfit Kappa on the EU merger control and foreign subsidies approvals and other merger control approvals across the globe in respect of its multi-billion value merger to form Smurfit WestRock.
- Advising Aon plc on the Irish merger control and FDI aspects of its acquisition of global insurance broker, NFP.
- Advising Macquarie Asset Management in relation to its agreement to acquire the Beacon Hospital in Dublin.
- Advising Bank of Ireland on the CCPC’s full Phase 2 investigation into the proposed acquisition of the assets of KBC Bank Ireland, including the agreement of commitments with the CCPC to secure approval.
- Advising AIB plc on the merger control, State aid and regulatory aspects of various transactions including its establishment of a life insurance joint venture with Irish Life, its establishment of the ‘Yippay’ mobile app joint venture with the other retail banks and the establishment of the ‘Nifti’ car leasing joint venture with Nissan Ireland.
- Advising Link Group on the CCPC’s Phase 2 investigation into the proposed acquisition of sole control of Pepper Ireland.
- Advising Goodman Group on the Irish merger control aspects of its creation of Ireland’s largest private hospital group, the Blackrock Healthcare Group.
Competition Enforcement, Litigation and Compliance
- Advising on the compliance with, and defending against enforcement of, the Digital Markets Act, the Digital Services Act and various other EU digital regulations.
- Advising Brokers Ireland on the CCPC investigation into the private motor insurance sector, which lasted from 2016 to 2021 and involved witness summonses and extensive information requests.
- Advising a multinational investment bank on its participation in a European Commission investigation into alleged anti-competitive conduct, including advising on related regulatory considerations vis-à-vis the UK Financial Conduct Authority.*
- Advising on dawn raids by EU and other national regulators, including attending a 2015 national regulator raid of a media advertising business in the UK and advising on identifying and mitigating risk after the raid.*
- Advising a multinational conglomerate on multiple European Commission competition law investigations and appeals against European Commission fining decisions before the EU courts, including a successful appeal against the European Commission’s CRT fining decision leading to a €28 million reduction in fines.*
- Advising a wide rage of clients on competition law compliance and dawn raid training, including dawn raid simulation exercises.
State aid / Procurement
- Advising on State aid issues associated with obtaining State funding for clients, including in crisis situations and through obtaining European Commission approval.*
- Advising Sport Ireland on its development of the National Indoor Arena.
- Advising the national postal operator on a wide range of procurement and State aid law issues, including its own procurement tenders, including most recently its roll-out of electric vehicles and related charging points and engagements with a disappointed bidder.
- Advising numerous third parties across sectors on procurement law challenges against tender competitions run by various State authorities and Semi-State bodies.
Sectoral Regulation / EU Regulatory Law
- Advising the national postal operator on a range of regulatory and competition law issues.
- Advising in relation to investigations and litigation involving the Irish aviation regulator.
- Advising a range of clients on registration, compliance and contentious issues under various product regulatory regimes including in the batteries, toys, chemicals, payment terminals and general manufacturing sectors.
- Advising companies subject to audit investigations by EU agencies, including audits of grant funding by the European Commission and the EU Anti-Fraud Agency (OLAF).
* Matter undertaken at previous firm
“Calum Warren at Matheson LLP, Dublin is extremely detail-oriented, perceptive and client-focused. He really listens to the needs of his clients and takes everything on board. He is very thorough, confident in his views, and very pragmatic as well. He can explain what the law is and what the limits are, but he always very successfully applies the framework to the facts at hand.”
Chambers 2024
“Calum Warren's client service and general level of service is very strong. His level of sophistication is very strong. His commercial vision is very strong. He is a pleasure to work with. He is thoroughly professional throughout, commercially aware, pragmatic and diligent.”
Chambers 2024
“Calum Warren is a bilingual German-speaking lawyer who is totally immersed in competition law. He has really thorough international training and has worked at White & Case…I would be using him on our most complex matters. What I'm really impressed with is that Calum is super involved. He's very tied in to all the relevant enforcers and he's also really well liked, which makes a huge difference in terms of getting on the right foot quickly. What is really special about [Matheson], as a practice in general but also with Calum Warren in particular, is that he is extremely knowledgeable in his subject. He is very well known by the officials in the EU and Ireland, and he has a "walk through walls" attitude in terms of getting the job done for his clients.”
Chambers 2024
“Calum Warren is excellent, with very timely turnarounds on advice. Gives sound, workable solutions.”
Legal500 2024
“Calum Warren is a rising star in the team, he is a very solid pair of hands for Irish merger control matters.”
Legal500 2024
“Calum Warren has worked in Brussels, the UK and Dublin, all in the top competition firms and within the European Commission and his breadth of experience is exceptional. I have seen him engage with competition enforcers in the UK, Ireland and from the European Commission and he is highly respected.”
Legal500 2024
"Calum Warren is excellent, very practical, excellent availability and he explains complex topics very clearly"
Legal500 2023
“Calum Warren provides excellent advice, is very solution focused and practical, as well as being incredibly responsive. All very valuable when trying to address complex issues in a commercial environment”
Legal500 2023
“Calum Warren provides excellent client service and is very knowledgeable”
Legal500 2022
Qualified as a solicitor in Ireland
King’s College, London (Post-Graduate Diploma in Economics for Competition Law)
Ludwig-Maximilians-Universität (LMU), Munich (LL.M. in European and International Business Law)
Trinity College Dublin (LL.B. in Law and German, First Class Honours)