Orange County’s Top Accounting and Business Advisory Firms in 2025
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Business by LA Times Studios presents the 20 largest accounting and business advisory firms ranked by the number of CPAs in Orange County offices. Deloitte is the largest firm in Orange County with 237 CPAs and more than 1,000 total staff in the area.
Ernst & Young LLP ranked No.2 with 180 CPAs in Orange County and PwC ranked No.3 with 151 CPAs. The largest local firm is independent Haskell & White LLP. The Irvine-based firm has 42 CPAs in its local office and a total local staff of 84 employees. The firm has a second office located in San Diego.
CBIZ acquired Marcum LLP, effective November 1, 2024. The numbers reported are reflective of post-transaction. Overall, the 20 largest firms employ 1,422 CPAs in Orange County and have more than 4,000 total staff.
