Big Four (audit Firms)

Big Four (audit Firms)

The Big Four are the four largest international professional services networks in accountancy and professional services, offering services including Audit, Assurance, Tax, Consulting, Advisory, Actuarial, Corporate Finance and Legal. They handle the vast majority of audits for publicly traded companies as well as many private companies, creating an oligopoly in auditing large companies. It is reported that the Big Four audit all but one of the companies that constitute the FTSE 100, and 240 of the companies in the FTSE 250, an index of the leading mid-cap listing companies. The Big Four firms are shown below, with their latest publicly available data.

This group was once known as the "Big Eight", and was reduced to the "Big Five" by a series of mergers. The Big Five became the Big Four after the demise of Arthur Andersen in 2002, following its involvement in the Enron scandal.