What Are the Big Four Accounting Firms?

By Matthew Frankel, CFP – Updated Nov 23, 2025 at 5:25 PM

Key Points

Big Four firms dominate 74% of global accounting market, influencing public company audits.
Merges reduced the Big Eight to Four major firms, intensifying industry concentration.
Big Four, private entities, guide crucial accounting standards and tax interpretations.

For many years, the accounting industry has been top-heavy, dominated by a small number of large and powerful firms. Over time, the largest accounting firms in the world underwent a series of mega-mergers, concentrating the industry even more.

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Hand is writing on a sheet of paper with a calculator. — Image source: Getty Images

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Mergers and Acquisitions

The consolidation of companies through various transactions like mergers, acquisitions, or takeovers.

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About the Author

Matt Frankel, CFP, is a contributing Motley Fool stock market analyst and personal finance expert covering financial stocks, REITs, SPACs, and personal finance. Prior to The Motley Fool, Matt taught high school and college mathematics. He holds a bachelor’s degree in physics from the University of South Carolina, a master’s degree in mathematics from Nova Southeastern University, and a graduate certificate in financial planning from Florida State University. He won a SABEW award for coverage of the 2017 Tax Cuts and Jobs Act. He is also regularly interviewed by Cheddar, The National Desk, and other TV networks and publications for his financial, stock market, and investing expertise.

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