Grant Thornton's Australian Deal Extends PE-Backed Roll-Up

What the Australian acquisition involves

Grant Thornton US confirmed it has agreed to acquire Grant Thornton Australia as part of its plan to build a global advisory platform, according to a report by City AM. The transaction was "recommended by the board and would close later this year, subject to shareholder partner approval and standard regulatory conditions," the firm said.

The Australian affiliate is valued at approximately A$800m (roughly £425m), according to the Australian Financial Review. At that price, the deal would be consistent with typical mid-tier professional services M&A multiples and would bring Grant Thornton US's total enterprise value to approximately 3.5 times that of Grant Thornton UK, based on City AM's analysis.

Grant Thornton US said the acquisition will "bring additional scale and momentum tied to the Australian firm's annual revenues" and "benefit from Grant Thornton Australia's market strength and reputation for quality."

Jim Peko, chief executive of Grant Thornton US, said the proposed deal will allow the firm to "build a differentiated platform with scale and purpose." Said Jahani, chief executive of Grant Thornton Australia, said that joining the platform "would give us accelerated access to emerging tech capabilities and growth capital, accelerating our ambition to build Australia's most modern, internationally aligned professional services firm."

The firm also indicated it plans to expand its AI capabilities and open new career pathways for graduates as part of the integration.

The PE playbook behind Grant Thornton's expansion

The Australian deal follows a clear sequence. In March 2024, Grant Thornton US sold a majority stake in its business to New York-based private equity firm New Mountain Capital. That transaction provided the capital base and corporate structure needed to pursue bolt-on acquisitions across the Grant Thornton network.

The model was quickly replicated in the UK. In December 2024, Grant Thornton UK partners voted unanimously to accept a private equity investment from Cinven, making it the largest professional services firm in the country to take external PE capital, as reported by City AM. The UK arm subsequently reported net revenue growth from £654m to £724m in the year to December 2024, representing double-digit percentage growth.

By November 2025, the PE-backed UK business had announced plans to hire 160 new partners over the following two years, a significant expansion of capacity.

The Australian acquisition represents the next stage: using the US platform, now backed by New Mountain Capital, to absorb network affiliates and consolidate them under a single, centrally capitalised entity. It is a roll-up strategy more commonly associated with private equity's approach to fragmented industries such as veterinary services, dental practices, or wealth management. Applied to professional services, it allows a mid-tier firm to build scale rapidly without the organic growth timelines that have historically constrained partnerships.

What this means for UK mid-market clients

Grant Thornton's UK and international operations serve a substantial base of mid-market and scale-up businesses. The firm's traditional strength has been offering audit, tax, and advisory services to organisations that sit below the Big Four's core client base but require more than a regional practice can provide.

The injection of PE capital changes the economics of that relationship. With external funding, Grant Thornton can invest in technology, hire senior specialists, and pursue cross-border integration in ways that were previously difficult under a partnership model where capital came from partners' own pockets.

For UK SMEs and scale-ups that use Grant Thornton or similar mid-tier firms, the consolidation trend raises several practical questions. A more globally integrated Grant Thornton may offer deeper capabilities in areas such as cross-border tax structuring, international expansion advisory, and technology-enabled audit. It may also bring pricing pressure as the firm seeks to deliver returns to its PE backers.

The shift also has implications for competition. If Grant Thornton's PE-backed model proves successful, rival mid-tier networks such as BDO, RSM, and Mazars may face pressure to pursue similar strategies or risk losing ground. That could accelerate consolidation across the sector, reducing the number of independent mid-tier options available to UK businesses.

How the mid-tier advisory landscape is shifting

Grant Thornton's trajectory sits within a broader pattern of structural change across professional services. The Big Four have explored external capital in various forms, with mixed results. EY's proposed split of its audit and advisory businesses collapsed in 2023 amid internal disagreements over strategy and economics. PwC has pursued restructuring efforts in several markets. Neither has yet taken on external equity investment at the parent level.

The mid-tier firms, less constrained by the regulatory scrutiny and internal complexity of the Big Four, have moved faster. Grant Thornton's deals with New Mountain Capital and Cinven represent the most prominent examples, but they are not isolated. Private equity firms have been circling the professional services sector for years, attracted by recurring revenues, sticky client relationships, and the potential to drive margin improvement through technology and operational efficiency.

The risk, as with any PE-backed consolidation, lies in execution. Integrating partnership cultures across jurisdictions is notoriously difficult. The Australian deal will test whether Grant Thornton can absorb an affiliate with its own established client base, regulatory environment, and professional norms without disrupting service quality.

There is also the question of exit. PE investors typically operate on a three-to-seven-year horizon. New Mountain Capital's investment in Grant Thornton US will eventually need to generate a return, whether through a secondary sale, an IPO, or further consolidation. The strategic decisions made now, including the Australian acquisition, will be shaped in part by that timeline.

For UK finance directors and board members, the message is pragmatic rather than dramatic. The firms that audit accounts, advise on transactions, and structure tax affairs are changing ownership and operating models. That does not necessarily change the quality of the work, but it does change the incentives behind it. Understanding those incentives is part of managing the advisory relationship effectively.

The Grant Thornton model is, for now, the clearest example of how PE capital can reshape a mid-tier professional services network into something that competes more directly with the Big Four. Whether it succeeds will depend on whether scale and capital can substitute for the decades of institutional depth that firms such as Deloitte, PwC, KPMG, and EY have built. The Australian deal is the latest test of that proposition.