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Work 028 9002 2520
Fax 0845 280 0108
Belfast, Belfast BT2, Bristol, Douglas, Guernsey, London

John McMahon

Work 028 9002 2520
Keystone Law

Work Department

Corporate, Commercial


John is a solicitor qualified to practise in three jurisdictions: Northern Ireland, England and Wales and the Republic of Ireland. John is also admitted as a Barrister and an Attorney in Bermuda. With particular expertise in corporate, commercial and intellectual property matters, his career has included a number of years spent in private practice as well as in-house. John also has a particular interest in advising clients in the property, energy, retail, hospitality, sport and general contracting industries.


2017 Keystone Law (NI) | Managing Director
2016-2017 McMahon McKay | Director/Principal
2007-2015 Johnsons Belfast | Partner
2001-2006 Appleby Bermuda | Senior Counsel
1997-2001 Halliwells Manchester | Partner
1993-1997 Eversheds Manchester | Assistant Solicitor
1993 Qualified as a solicitor in England & Wales
1991-1993 Eversheds Manchester | Trainee Solicitor

Northern Ireland: Corporate and commercial

Corporate and M&A

Within: Corporate and M&A

Following its merger with commercial law boutique McMahon McKay in 2017, Keystone Law  is very well known for its track record on M&A and investment work. The group represents buy-side and sell-side clients from a range of sectors, including manufacturing and real estate. Highlights included advising a prominent investment fund on the £70m investment in Halo Belfast, a 5-year cyber and economic development project. John McMahon  leads the team, in which J P Irvine  and Danny McKay  are key names.

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Northern Ireland: Real estate

Commercial property

Within: Commercial property

Keystone Law’s property team has ‘a practical, commercial approach to resolving legal issues’ and provides ‘advice that is tailored to the matter in hand’. The group advises companies and individuals on leases and acquisitions for hotel, retail and residential developments, as well as handling landlord and tenant matters. In a standout mandate, the firm advised Belfast-based property group Kilmona on its £90m refinancing of its group banking facilities with Fairfield Real Estate Finance. Jim Houston jointly heads the practice with Danny McKay . John McMahon is another key name.

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Legal Developments worldwide

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  • The Cayman Islands Data Protection Law, 2017

    The following information relates to the enactment of The Cayman Islands Data Protection Law, 2017 (" DPL "), which was expected to come into force on 29 January 2019, will now come into force in September 2019. The DPL will regulate the future processing of all personal data in the Cayman Islands.
  • The Mutual Funds Law (2019 Revision)

    The following information relates to the enactment of The Mutual Funds Law (2019 Revision) and the subsequent commencement of related sections of The Mutual Funds (Amendment) Law 2015. The changes require certain funds to notify the Cayman Islands Monetary Authority if they are active in EU jurisdictions.
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    - Dorda
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