BDO Nears Landmark UK-Ireland Merger as Mid-Tier Firms Pursue Scale

BDO UK and BDO Ireland are in the final stages of current merger talks. The deal, pending partner and regulatory approval, would combine the existing 18 UK offices with Irish operations, generating a merged firm with approximately £1.1bn in annual revenues, and spanning a network of 542 partners and 8,500 staff. The merged entity would place BDO firmly amongst the top regional players and strengthen BDO’s hold on the market as the world’s fifth-largest accounting organisation. Broadly speaking, the deal represents a wider shift towards regional consolidation across the professional services industry and is a major milestone in BDO’s journey to growth.

BDO currently operates as a global network of independently owned partnerships, each managed locally, but altogether united under the BDO International Umbrella. There is a long-standing relationship between the UK and Irish firms, as they have consistently collaborated closely for over four decades; naturally, this presents the proposed merger as a logical step forward towards deeper integration. Consequently, the proposed merger would formally unite the two markets under a single business structure, while maintaining their integration with the wider BDO global network, which spans 166 countries and employs more than 119,000 professionals across 1,800 offices. Altogether, this alignment reflects a shared ambition not only to strengthen their joint partnership, but broader intentions to better serve client interests whose operations are increasingly extending across borders.

Both leadership teams described the merger as a natural evolution driven by changing client needs. Mark Shaw, managing partner of BDO UK, stated that the proposal “demonstrates the ambition we have for our business, our people, and our clients,” adding that mid-market businesses “are increasingly looking for support on a range of cross-border issues.” His counterpart in Ireland, Brian McEnery, further framed the deal as a “logical step,” building on the foundations of their shared culture and a mutual commitment to people, quality, and integrity. Both Leaders have pointed to the growing demand for integrated advisory, audit, and tax services across international jurisdictions. And so, as markets become increasingly interconnected, the merger aims to deliver conjoined expertise while enforcing the company’s pre-existing mid-market focus, a key segment often underserved by the ‘Big Four’ firms.

The proposed merger comes amid accelerating consolidation within the middle-market landscape. While the Big Four have long dominated globally, firms like BDO, Grant Thornton, and RSM are now pursuing regional integration strategies to compete more effectively and achieve greater scale. Grant Thornton recently decided to sell a stake in its UK business to private equity firm Cinven, marking a watershed moment, to fund its acquisitions in Germany and Singapore. Contrarily, BDO’s strategy is instead partner-led and, therefore, not driven by external investors; this means that the merger aims to support scale without compromising independence. However, the global network is exploring a range of investment options, including debt financing or partial equity sales, to aid further consolidation. Many analysts say that such moves reflect the sector’s growing need to deliver cross-border services and invest increasingly in technology and talent. For BDO, the UK-Ireland combination strengthens its platform across two dynamic, yet closely linked, economies.

Regarding the benefits of the merger, BDO has high hopes for the advancements it can deliver. It promises to unlock new investments in people, technology, and cross-border collaboration. The combined firms will improve their ability to diversify their service mix of audit, tax, deals, consulting, risk and outsourcing. Both firms are confident that the greater scale will enable them to make larger investments in innovation and emphasise that staff development will further improve with expanded career development opportunities. Clients are expected to benefit from a deeper pool of expertise and more consistent support as they grow internationally. BDO’s management sees the integration as a means to achieve stronger returns on investment and to position the business for sustainable long-term growth, particularly within the fast-evolving mid-market space.

The merger remains subject to partner votes and regulatory approval, with completion anticipated once those hurdles are cleared. Integration will likely focus on harmonising operations and governance, while maintaining each firm’s local expertise and relationships. If approved, the deal would represent more than an operational realignment; it would mark a strategic statement about the future of professional services. In an industry where scale, agility and cross-border capability increasingly define success, BDO’s UK-Ireland merger signals a clear intent to lead regional consolidation. For the mid-market clients it serves, the move could redefine what integrated, entrepreneurial advisory support looks like in the years ahead.