Professional services firm AAB has agreed a business combination deal with UK accountancy and business advisory practice Kreston Reeves.

The combined group is expected to have an annual revenue of more than £200m ($273m).

AAB chief executive Emma Lancaster said: “This is a major milestone for AAB and a clear demonstration of our ambition to become the leading professional services firm serving the mid-market.

“Growing the group beyond £200m revenue is not about growth for growth’s sake – it is about building a resilient, sustainable business that delivers long-term value for our clients, our people and our communities.”

Kreston Reeves operates seven offices across London, Kent and Sussex, and employs around 550 people.

AAB, backed by Goldman Sachs Alternatives, focuses on mid-market professional services and has completed 18 transactions across the UK and Ireland over the past four years.

The agreement reflects ongoing consolidation in the accounting sector and rising competitive pressures across the market.

The companies said the combination will support further investment by Kreston Reeves in staff, technology and tools, enabling services to be delivered to clients.

For AAB, the deal extends its footprint in London and the South East, with Kreston Reeves set to act as its regional hub.

Kreston Reeves managing partner Richard Spofforth said: “This is a significant milestone for our business, people and clients. Building on the strengths we have at Kreston Reeves, it will create new opportunities for our talented colleagues.”

Once combined with Kreston Reeves, AAB will employ more than 1,800 people across 23 locations in the UK and Ireland.

The transaction is subject to regulatory approval and is expected to close in spring 2026.