BDO Ireland and BDO UK have announced a proposed merger of the two organisations after a successful partner vote for the move.
Completion of the merger is expected in Spring of this year - subject to regulatory approval.
The enlarged organisation will bring together BDO's Irish offices in Dublin and Limerick with the UK firm's 17 offices.
The new business will have revenues of about €1.26 billion, about 550 partners and 8,500 employees.
It will remain part of the $11 billion BDO international network, which spans 169 counties and territories and has more than 95,000 people working out of 870 offices worldwide.
BDO said today's "in-network" merger deal is a major milestone for both organisations, cementing its position as one of the largest accountancy firms in Europe,
The merger will broaden its offering across its four core service lines - Audit, Tax, Deals and Consulting, Risk & Outsourcing - and in a range of growth sectors across the Irish and UK economies.
Brian McEnery, Managing Partner at BDO Ireland, said the two companies have worked side-by-side for decades on cross-border engagements, client collaborations and talent exchanges.
"We know each other well and this shared history gives us confidence that we can build something even stronger together," he added.
Mark Shaw, Managing Partner at BDO UK, said that partners in both the UK and Ireland are excited about the next phase of BDO's growth story and are pleased to have reached this important stage in the deal.
"This is a merger built on a foundation of shared culture, with mutual respect and commitment to our people, to quality and the consistency of service which our client heartland of entrepreneurial, growing and ambitious businesses requires. We look forward to working, thriving and winning together," he added.
