Hervé Daniel Marcel Falciani (Italian: [falˈtʃaːni]; born 9 January 1972) is a French-Italian systems engineer and whistleblower who is credited with "the biggest banking leak in history." In 2008, Falciani began collaborating with numerous European nations by providing allegedly illegal stolen information relating to more than 130,000 suspected tax evaders with Swiss bank accounts – specifically those with accounts in HSBC's Swiss subsidiary HSBC Private Bank.