Panama Papers Q&A: What is the scandal about?

What are the Panama Papers?
The files show how Mossack Fonseca clients were able to
launder money, dodge sanctions and avoid tax.
In one case, the company offered an American millionaire
fake ownership records to hide money from the authorities.
This is in direct breach of international regulations designed to
stop money laundering and tax evasion.
It is the biggest leak in history, dwarfing the data released by
the Wikileaks organisation in 2010. For context, if the amount
of data released by Wikileaks was equivalent to the population
of San Francisco, the amount of data released in the Panama
Papers is the equivalent to that of India.
You can find our special report on the revelations here .
Who is in the papers?
There are links to 12 current or former heads of state and
government in the data, including dictators accused of looting
their own countries.
More than 60 relatives and associates of heads of state and
other politicians are also implicated.
The files also reveal a suspected billion-dollar money
laundering ring involving close associates of Russia's
President, Vladimir Putin.
Also mentioned are the brother-in-law of China 's President Xi
Jinping ; Ukraine President Petro Poroshenko ; Argentina
President Mauricio Macri; the late father of UK Prime Minister
David Cameron and three of the four children of Pakistan 's
Prime Minister Nawaz Sharif .
The documents show that Iceland 's Prime Minister, Sigmundur
Gunnlaugsson , had an undeclared interest linked to his wife's
wealth. He has now resigned.
The scandal also touches football's world governing body,
Fifa .
Part of the documents suggest that a key member of Fifa's
ethics committee, Uruguayan lawyer Juan Pedro Damiani, and
his firm provided legal assistance for at least seven offshore
companies linked to a former Fifa vice-president arrested last
May as part of the US inquiry into football corruption.
The leak has also revealed that more than 500 banks,
including their subsidiaries and branches, registered nearly
15,600 shell companies with Mossack Fonseca.
Lenders have denied allegations that they are helping clients
to avoid tax by using complicated offshore arrangements.
How do tax havens work?
Although there are legitimate ways of using tax havens, most
of what has been going on is about hiding the true owners of
money, the origin of the money and avoiding paying tax on the
money.
You can read more on how tax havens work here .
Some of the main allegations centre on the creation of shell
companies, that have the outward appearance of being
legitimate businesses, but are just empty shells. They do
nothing but manage money, while hiding who owns it.
One of the media partners involved in the investigation,
McClatchy, has more on how shell companies work in this
video .
What do those involved have to say?
Mossack Fonseca says it has operated beyond reproach for 40
years and never been accused or charged with criminal wrong-
doing.
Mr Putin 's spokesman Dmitry Peskov said the reports were
down to "journalists and members of other organisations
actively trying to discredit Putin and this country's leadership".
Publication of the leaks may be down to "former employees of
the State Department, the CIA, other security services," he
said.
In an interview with a Swedish television channel, Mr
Gunnlaugsson said his business affairs were above board and
broke off the interview.
Fifa said it is now investigating Mr Damiani , who told Reuters
on Sunday that he broke off relations with the Fifa member
under investigation as soon as the latter had been accused of
corruption.
Who leaked the Panama Papers?
The 11.5m documents were obtained by the German
newspaper Sueddeutsche Zeitung and shared with the
International Consortium of Investigative Journalists (ICIJ).
The ICIJ then worked with journalists from 107 media
organisations in 76 countries, including UK newspaper the
Guardian , to analyse the documents over a year.
The BBC does not know the identity of the source but the firm