The Big Four are the four largest international professional services networks, offering audit, assurance, tax, consulting, advisory, actuarial, corporate finance, and legal services. They handle the vast majority of audits for publicly traded companies as well as many private companies. It is reported that the Big Four audit 99% of the companies in the FTSE 100, and 96% of the companies in the FTSE 250 Index, 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 Six" and then "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.