The Panama Papers are a leaked set of 11.5 million confidential documents that provide detailed information about more than 214,000 offshore companies listed by the Panamanian corporate service provider Mossack Fonseca, including the identities of shareholders and directors of the companies. The documents show how wealthy individuals, including public officials, hide their money from public scrutiny. At the time of publication, the papers identified five then-heads of state or government leaders from Argentina, Iceland, Saudi Arabia, Ukraine, and the United Arab Emirates; as well as government officials, close relatives, and close associates of various heads of government of more than forty other countries, including Brazil, China, France, India, Malaysia, Mexico, Pakistan, Peru, Romania, Russia, South Africa, Spain, Syria, and the United Kingdom. The UK was singled out by the media as being "at the heart of [a] super-rich tax-avoidance network".
While the use of offshore business entities is not illegal in the jurisdictions in which they are registered, during their investigation reporters found that some of the shell companies may have been used for illegal purposes, including fraud, drug trafficking, and tax evasion.
The documents were made available to the Süddeutsche Zeitung beginning in early 2015 by an anonymous source, an unremunerated whistleblower using the pseudonym "John Doe". The information documented actions going back to the 1970s and eventually totaled 2.6 terabytes of data. Given the scale of the leak, the newspaper enlisted the help of the U.S.-based International Consortium of Investigative Journalists (ICIJ) which is funded by many US-based foundations and private donations, distributed documents for investigation and analysis to some 400 journalists at 107 media organizations in 76 countries. The first news reports based on the papers, and 149 of the documents themselves, were published on April 3, 2016. The ICIJ promises to publish a full list of companies involved in early May 2016.