Grant Thornton to Buy CBIZ for $5 Billion in Major Accounting Consolidation

Blockbuster Deal Creates Fifth-Largest U.S. Accounting Firm

Grant Thornton Advisors will acquire CBIZ for $5 billion in cash, the companies announced on Wednesday, July 29, forging one of the largest accounting services providers in the United States. The transaction, representing the biggest deal of its kind in more than 25 years, propels Grant Thornton past four competitors to become the fifth-largest U.S. provider of professional, tax, and advisory services. The combined entity will trail only the Big Four firms-Deloitte, EY, KPMG, and PwC-and will generate nearly $7.5 billion in global revenue. Grant Thornton currently ranks ninth on Accounting Today’s 2026 list, making this acquisition a dramatic leap forward in scale and market reach.

CBIZ shareholders will receive $55 per share, a 17.8% premium to the stock’s previous closing price, and roughly a 54% premium to the firm’s 30-day volume-weighted average share price. The market reacted immediately, with CBIZ shares jumping 17.5% in premarket trading. Upon closing, CBIZ-currently the only publicly traded accounting firm-will be wholly owned by Grant Thornton Advisors, cease trading, and no longer be listed on the New York Stock Exchange.

Strategic Vision Behind the Combination

Jim Peko, CEO of Grant Thornton Advisors and leader of the firm’s multinational platform, emphasized the strategic rationale behind the merger. The combined organization will span more than 20 countries and territories, significantly expanding Grant Thornton’s geographic footprint and service capabilities. The transaction aims to enhance Grant Thornton’s artificial intelligence capabilities, grow its multinational reach, and expand both industry specialization and service offerings across diverse market segments.

“By combining our multinational platform with CBIZ’s strong market presence, we’re broadening our ability to support businesses through every stage of growth – from early development to global scale,” Peko said. “Together, we’ll bring the quality, scope and capabilities clients need to navigate an increasingly complex and rapidly evolving business environment.”

Jerry Grisko, president and chief executive officer of CBIZ, described the transaction as transformational for both firms. The CBIZ board of directors unanimously approved the transaction and recommended that shareholders vote in favor of the deal, signaling strong confidence in the strategic fit and value creation potential.

Rapid Consolidation Reshapes Mid-Tier Accounting Landscape

The Grant Thornton-CBIZ combination represents the latest milestone in rapid consolidation sweeping the U.S. accounting sector, as mid-tier firms race to close the gap with the Big Four. Baker Tilly and Moss Adams merged last year in a $7 billion deal, setting a precedent for mega-mergers in the professional services space. CBIZ itself, which focuses on the middle-market segment, acquired accounting firm Marcum in a $2.3 billion transaction in 2024, demonstrating the firm’s own aggressive expansion strategy before becoming an acquisition target.

Grant Thornton has been on an expansion spree since receiving investment from a consortium led by buyout firm New Mountain Capital in 2024. The private equity backing has accelerated Grant Thornton’s growth trajectory, providing the capital and strategic support needed to pursue transformative acquisitions. New Mountain is making a new equity investment to support the CBIZ transaction, continuing its commitment to building Grant Thornton into a formidable competitor to the Big Four.

Regulatory Outlook and Deal Structure

Andrew Nicholas, an analyst at William Blair, offered reassurance regarding potential regulatory hurdles facing the transaction. The fragmented nature of the accounting industry and the relatively small post-merger market share for the combined organization suggest that regulatory approval should not be an issue, according to Nicholas. The merged entity will still hold a modest share of the overall U.S. professional services market, reducing antitrust concerns that might accompany consolidation in more concentrated industries.

The transaction includes a “go shop” provision that allows CBIZ to actively solicit competing offers until August 27. This period enables CBIZ to test the market and ensure shareholders receive maximum value, though the unanimous board approval suggests management views the Grant Thornton offer as compelling. Goldman Sachs advised CBIZ on the transaction, while Deutsche Bank serves as the lead financial adviser for Grant Thornton Advisors.

Post-Merger Structure and Spin-Off Plans

Following the deal’s expected close in the fourth quarter of 2026, Grant Thornton plans to implement a strategic restructuring of CBIZ’s business portfolio. The firm will separate CBIZ’s benefits and insurance services segment into an independent company backed by New Mountain Capital. This spin-off strategy allows Grant Thornton to focus on its core accounting, tax, and advisory services while creating value from CBIZ’s complementary but distinct insurance operations.

“This is a historic combination with a complementary cultural and strategic fit,” Grisko said. “CBIZ has grown rapidly over many years to become a leading professional services provider. Joining Grant Thornton Advisors accelerates the realization of that vision, creating a stronger firm with new and exciting opportunities for our team members and enhanced service offerings for clients, while delivering significant value to CBIZ shareholders.”

New Mountain Capital’s Expanding Role

Andre Moura, managing director of New Mountain Capital, expressed enthusiasm for continuing the strategic partnership with Grant Thornton. The private equity firm’s involvement since May 2024 has positioned Grant Thornton for aggressive expansion, and the CBIZ acquisition represents the largest step yet in building a formidable alternative to the Big Four dominance. New Mountain’s dual role-backing both the Grant Thornton platform and the future independent benefits and insurance company-demonstrates sophisticated portfolio construction and value creation strategy.

“We’re pleased to continue to support Grant Thornton Advisors’ strategic growth plan, a journey we have been on together since May 2024,” Moura said. “Following the acquisition of CBIZ, Grant Thornton in the U.S. will be the fifth largest professional services” firm in the nation.

The accounting industry faces mounting pressures from technological disruption, regulatory complexity, and client demands for integrated services, making scale increasingly critical for competitive survival. The Grant Thornton-CBIZ merger positions the combined firm to compete more effectively with the Big Four while offering clients enhanced capabilities, deeper industry expertise, and broader geographic reach across both domestic and international markets.