
Mason Hayes & Curran LLP has continue to make its mark in high-value cross-border M&A and private equity investments, while maintaining its presence in domestic and mid-cap transactions. The firm has close links to fast-growth global companies and has a fine record in the energy, technology, healthcare and life sciences, and built environment sectors. It remains noted for advising US and other global companies on their acquisitions and investments in Ireland. David O’Donnell is hugely experienced, while public M&A expert Justin McKenna and head of corporate Martin Kelleher are also highly-rated practitioners. Claire Lord leads the corporate governance and compliance team. William Dillon-Leetch and Conall Geraghty also impress.
Testimonials
Collated independently by Legal 500 research team.
‘The team are technically excellent and very responsive.’
‘William Dillon-Leetch has an in depth knowledge of the legal aspects and commercial approach to transactions. His client-relationship skills are also excellent.’
‘Dermot McGirr and the team at MHC supported us with advice on a complex and novel legal matter. Their advice, while always addressing the legal risks and requirements, also always considered the commercial implications for our business. Their guidance was a great support. ’
‘Justin McKenna is superb. Fierce intellect, excellent on the intricacies of the Takeover Code. And a pleasure to work with. Ann Harkin is very good too. ’
‘Client first - extremely hard working and considered in their advice. ’
‘I frequently work with Dermot McGirr and have instructed him on a range of commercial matters. Dermot is a pleasure to work with and I regard him as a very safe pair of hands in the area. He is a trusted adviser to our team and his approach certainly makes him feel like an extension of our team itself. His response time is excellent and his advice is always well rounded yet commercially-focused .'
‘David O'Donnell is excellent, very experienced and dedicated to his clients.’
‘Robert Dickson is an outstanding commercial lawyer providing incisive advice into the transaction. His response is rapid and relevant. His team is excellent. With his advice, I always know what I need to do next and how to complete the deal.’
Key clients
- VentureWave Capital
- Elgin Energy Services
- Bencis Capital Partners
- AustralianSuper
- Ciaran Brennan, the sole shareholder of Kyron Innovative Technologies
- Workvivo
- Steripack Ireland
- MML Capital Ireland
- Seamus McGlade and Siloah Limited
- Strong Roots
- Enterprise Ireland
- AIB
- Kia Ireland
- Encirc
Work highlights
- Advised the VentureWave along with other investors on an investment in Funderbeam, an angel investing and trading platform.
- Acted for Elgin in its sale of a portfolio of 16 solar farm projects located across Ireland to Allianz Capital Partners.
- Acted as Irish counsel for AustralianSuper on its significant minority investment of €1.5bn in the Vantage Data Centers Group.
Lawyers

Practice head
The lawyer(s) leading their teams.
Martin Kelleher