Orange County’s Top Accounting and Business Advisory Firms in 2024

Below are the 20 largest accounting and business advisory firms ranked by the number of CPAs in Orange County offices. Overall, the 20 largest firms employ 1,340 CPAs in Orange County and have more than 4,700 total staff. Deloitte is the largest accounting firm in Orange County with 238 CPAs and more than 1,000 total staff in the area.

Ernst & Young LLP ranked No. 2 with 179 CPAs in Orange County and Moss Adams ranked No. 3 with 128 CPAs. The largest local firm is independent Haskell & White LLP. The Irvine-based firm has 50 CPAs in its local office and a total local staff of 88 employees. The firm has a second office located in San Diego.