Arthur Andersen LLP, based in Chicago, is a holding company and formerly one of the "Big Five" accounting firms among PricewaterhouseCoopers, Deloitte Touche Tohmatsu, Ernst & Young and KPMG, providing auditing, tax, and consulting services to large corporations. In 2002, the firm voluntarily surrendered its licenses to practice as Certified Public Accountants in the United States after being found guilty of criminal charges relating to the firm's handling of the auditing of Enron, an energy corporation based in Texas, which had filed for bankruptcy in 2001.