Credit Suisse has confirmed its offices in Milan have been searched by Italian tax police.
The raid last month is reportedly part of an investigation into whether a subsidiary of the bank helped wealthy Italians hide undeclared cash.
According to media reports say the searches focused on alleged tax evasion by around 1,000 Italians involving an estimated eight billion euros.
A Bermuda-based subsidiary of Credit Suisse, called Life and Pensions, is said to have offered insurance products that authorities suspect allowed clients to hide funds offshore.
The Italian tax police declined to comment.
German tax inspectors conducted a similar investigation of Credit Suisse clients in the summer of 2012.
The Italian raid is the latest in a series of investigations of Swiss banks, including Credit Suisse, involving their dealings with wealthy clients and hidden offshore accounts, against the backdrop of international pressure on Switzerland’s secrecy laws.