Arthur Andersen was an American accounting firm based in Chicago that provided auditing, tax advising, consulting and other professional services to large corporations. By 2001, it had become one of the world's largest multinational corporations and was one of the "Big Five" accounting firms (along with Deloitte & Touche, Ernst & Young, KPMG and PricewaterhouseCoopers). The firm collapsed by mid-2002, as details of its questionable accounting practices for energy company Enron and telecommunications company Worldcom were revealed amid the two high-profile bankruptcies. The scandals were a factor in the enactment of the Sarbanes-Oxley Act of 2002.