Grant Thornton South Africa's Johannesburg office is to merge with PKF Johannesburg, effective 1 July.
Based on International Accounting Bulletin data, the merger will add over ZAR100m ($11m) in annual revenue to Grant Thornton South Africa, increasing its revenue total to just over ZAR520m.
As a result of the merger, PKF Johannesburg will become part of Grant Thornton South Africa and Andrew Hannington, currently a board member of PKF International and chairman of PKF South Africa, will be.appointed chief executive of Grant Thornton Johannesburg.
"This is an incredibly exciting opportunity to work with a firm with similar goals and truly well-aligned cultures, coupled with a global force to be reckoned with," Hannington said.
"This is a merger of equals - combining PKF Johannesburg's strong market position with Grant Thornton's established brand and intellectual property. It unifies the strengths and specialised expertise of each entity resulting in a formidable firm which will be unparalleled in the mid-tier market."
The loss of PKF Johannesburg is the latest in a series for PKF International, which has lost several strong firms in mergers in the past 12 months, such as founding member PKF UK in a merger with BDO, and its East Coast Practice in Australia.
PKF International had seven member firms in South Africa at the end of last year, and the loss of PKF Johannesburg is likely to lead to a 32% drop in revenues in South Africa to around ZR220m, according to IAB data.
Grant Thornton South Africa said other PKF offices in South Africa will continue to trade under the PKF name and "will not be part of the merger at this stage".
"Mergers are a vital step in achieving our strategic ambitions and Grant Thornton is committed to fast and strategic growth with like-minded organisations and individuals. This merger is a truly significant step for Grant Thornton in South Africa and I am pleased to welcome the new partners and staff to our global organisation," Grant Thornton International global chief Ed Nusbaum said.
PKF International declined to comment on the news.