Top 10 accounting firm Grant Thornton is acquiring fellow top 10 firm CBIZ to form a firm that’s outsized only by the Big Four in terms of U.S. revenue. The transaction, expected to close in the fourth quarter of 2026 according to a news release, will result in Grant Thornton Advisors acquiring CBIZ in an all-cash transaction. Joining Grant Thornton Advisors accelerates the realization of that vision. When the transaction is completed, CBIZ will become wholly owned by Grant Thornton Advisors, and CBIZ common stock will cease to trade and will no longer be listed on the New York Stock Exchange. In 2024, CBIZ moved into the top 10 by acquiring fellow top 15 firm Marcum.