After Falciani, then an IT expert at HSBC's Swiss bank, hacked into the bank's customer files in late 2007 he triggered a major scandal, exposing stunning corruption within an industry built in the shadows. How the offshore banking industry shelters money and hides secrets has enormous implications across the globe: Experts conservatively estimate that $7.6 trillion is held in overseas tax havens, costing government treasuries at least $200 billion a year. As the information leaked by Falciani confirmed, Swiss banks have long been a cash-hoarding haven for those involved in illicit activities like drug running, political corruption and money laundering.

Hired in 2001 to create a client management database, Falciani soon came to realize that the way information was managed by the organization fostered tax evasion. After he proposed a new system, which was rejected by his superiors, Falciani spent the next two years collecting evidence on some 30,000 accounts holding almost $120 billion in assets. His attempt to make the information available to Swiss judicial authorities resulted in his arrest in Switzerland.

After his release on bail, Falciani fled to France, where his HSBC data trove ended up in the hands of authorities who subsequently indicted HSBC for illegal direct marketing to French nationals, money laundering and facilitating tax fraud. French authorities, including Christine Lagarde, now managing director of the International Monetary Fund, then shared the data with other countries, including the United States.