AC Arthur Cox More Arthur Cox is one of Ireland’s leading law firms. For almost 100 years, we have been at the forefront of developments in the legal profession in Ireland. Our practice encompasses all aspects of corporate and business law. The firm has offices in Dublin, Belfast, London, New York and Silicon Valley. 2025 was another milestone year for transactions involving professional services firms in Ireland. Alongside a busy transactional environment, there is an evolving regulatory landscape.