The Swiss leaks
In 2008, Falciani released details on thousands of clients he suspected were using accounts to evade tax.
The documents allege that HSBC helped more than 120,000 clients hide €180.6bn (£161.3bn, $199.8bn) between November 2006 and March 2007.
His leak has forced Swiss courts to rule on requests from other countries to help prosecute suspected tax dodgers who were included in the leaked information.
Last year, the Swiss Supreme Court rejected a French request for help in investigating a married couple for tax offences, ruling that the data stolen from HSBC was inadmissible.
But, on 2 August, the same Swiss court released its ruling on a request made by Indian authorities against two of its citizens and two companies.
The two citizens had argued their bank data should not be released as the request was based on stolen data, and therefore violated the principle of good faith.
The court disagreed with this defence and found that India should be allowed to get the assistance that it has asked for, since the country did not buy the stolen data from Falciani.
The court said that, unlike in the French case, India has made no explicit statements about how it obtained the data.
It is understood the leaked information relating the two citizens reached India through the French Government, which obtained the list of bank account holders from Falciani directly.
Further, the information-sharing agreement between Switzerland and India does not oblige the country making a request to reveal how it came by the data at the root of the demand.