The Swiss banking giant said it is cooperating with investigations.

Local authorities last week contacted three of Credit Suisse's European offices over tax matters related to client accounts, the Swiss bank said in a brief statement. Later, the lender took out advertisements to explain its position.

“Credit Suisse offices in London, Paris and Amsterdam were contacted by local authorities concerning client tax matters,” the Zurich-headquartered firm said. “We are cooperating with authorities.”

The bank's statement preceded an announcement from the Dutch office for financial crimes prosecution (FIOD) on Friday, which said prosecutors had launched probes in several countries after they were tipped off about millions of dollars of undeclared assets linked to accounts in an unnamed Swiss bank. 

Prosecutors said the assets were connected to 3,800 Dutch-linked accounts. In addition to the Netherlands, raids are under way in France, Germany, the UK and Australia. 

Credit Suisse offered no further comment on the matter in that statement late last week.

Paintings, a gold bar, cash, a luxury car and jewellery have been seized, FIOD said. Investigations will continue for several weeks, prosecutors said. 

In newspaper adverts, Credit Suisse said: “This led to very significant asset outflows as we do not want to do business with clients who are unwilling to provide the required evidence. Credit Suisse applies a strict zero tolerance policy on tax evasion.”