Grant Thornton has agreed to acquire CBIZ for $5 billion in an all-cash transaction, creating the fifth-largest professional services, tax and advisory provider in the United States. The definitive agreement was announced on July 29, 2026, marking the largest accounting industry deal in more than 25 years. CBIZ shareholders will receive $55 per share in cash, representing a 54% premium to the firm’s 30-day volume-weighted average share price.
Upon closing in the fourth quarter of 2026—subject to shareholder approval and regulatory clearances—Grant Thornton’s U.S. arm is expected to generate more than $5 billion in annual domestic revenue. The combined multinational platform will span more than 20 countries and territories, generate nearly $7.5 billion in global revenue and employ more than 34,500 professionals across the Americas, Europe, the Middle East and Asia-Pacific.
The deal builds on Grant Thornton’s recent $1 billion investment in artificial intelligence and advanced technologies. The combined firm will expand its ability to deliver AI-enabled service solutions to a broader client base and enhance its depth of specialized industry expertise and multinational reach, according to the company’s announcement.
CBIZ has grown rapidly through recent acquisitions. In November 2024, CBIZ completed its acquisition of Marcum LLP for $2.3 billion, a deal that positioned CBIZ as the seventh-largest accounting firm with approximately $2.8 billion in annual revenue. That transaction was itself one of the largest in the sector’s recent history. The Grant Thornton-CBIZ deal now surpasses it, underscoring accelerating consolidation in the accounting industry.
The accounting sector has seen record deal activity. Accounting firm mergers and acquisitions spiked 26% year-over-year in 2025, with a record 194 transactions announced or completed, according to industry data. The surge reflects firms’ need to scale, invest in technology and compete for talent in a market increasingly driven by AI and digital transformation.
New Mountain Capital’s Strategic Backing
Private equity firm New Mountain Capital is making additional equity investments to support the transaction. New Mountain previously led a significant investment in Grant Thornton Advisors in May 2024, giving it a stake in the firm’s growth strategy. The continued backing signals confidence in Grant Thornton’s acquisition and consolidation plan.
Following the deal’s close, Grant Thornton plans to separate CBIZ’s Benefits and Insurance Services segment into a new standalone entity, also backed by New Mountain Capital. This structure allows the insurance and retirement services business to operate independently while remaining supported by the same private equity investor.
Jim Peko, chief executive officer of Grant Thornton Advisors, said the combination will “broaden our ability to support businesses through every stage of growth—from early development to global scale.” CBIZ CEO Jerry Grisko called it “a historic combination with a complementary cultural and strategic fit,” noting that the deal accelerates CBIZ’s vision while delivering value to shareholders.
CBIZ’s Board of Directors has unanimously approved the transaction and recommended it to shareholders. The deal includes a go-shop provision allowing CBIZ to solicit alternative proposals through August 27, 2026, though no assurance exists that a superior offer will emerge. The transaction is supported by major financial advisors including Goldman Sachs (for CBIZ), Deutsche Bank, J.P. Morgan, and other leading investment banks.
Sources
- Grant Thornton — official press release on the definitive merger agreement, deal terms, transaction timing, and strategic rationale
- Reuters — reporting on the $5 billion all-cash deal, New Mountain Capital’s role, and expected closing timeline
- Wall Street Journal — coverage of the enterprise value, deal structure, and Grant Thornton’s positioning as fifth-largest firm
- CBIZ — investor relations announcement on the acquisition agreement and shareholder terms
- CPA Practice Advisor — data on accounting firm M&A trends showing record 2025 transaction volume and 26% year-over-year growth
- Crain’s Cleveland — reporting on CBIZ’s completed Marcum acquisition in November 2024 and the firm’s resulting ranking as seventh-largest
