With the audit market concentrated among the four largest firms, concerns have been raised about the number of choices that companies have when selecting an auditor and the extent of competition in the market. In 2003, we conducted a study (mandated by the Sarbanes-Oxley Act) on consolidation that had occurred in the accounting profession. Our study followed the dissolution of one of the then-five largest accounting firms, Arthur Andersen. At that time, we found that although audits for large public companies were highly concentrated among the largest accounting firms, the market for audit services appeared competitive according to various indicators. 6 .
