The newspaper said the Institute of Religious Works (IOR) and 10 Italian banks, including major institutions such as Intesa San Saolo and Unicredit, were the target of the investigation.
'The hypothesis of the investigators is that subjects with their fiscal residence in Italy are using the IOR as a 'screen' to hide different dealings, such as fraud or tax evasion,' the paper said.
The IOR manages bank accounts for religious orders and Catholic associations and benefits from Vatican offshore status.
Investigators have uncovered transactions of around 180 million euros (S$310 million) over a two-year period in one of the accounts held at the IOR.In September 2009 the IOR nominated a new chief executive, Ettore Gotti Tedeschi, Spanish banking giant Santander's representative in Italy.
US archbishop Paul Marcinkus headed up the bank in 1971-1989 during which time it was caught up in scandals including the collapse of the private Italian bank, Banco Ambrosiano in 1982 amid accusations of links to the mafia and political terrorism.