Swiss bank secrecy has come under heavy pressure in recent years as cash-strapped governments have sought to fight tax evasion.
In a webcast of a presentation to a conference in New York, finance chief David Mathers said Credit Suisse had already seen more than 30bn francs (£20bn) in net outflows from mature offshore markets since 2009, part of it due to the tax disputes.
“Cross-border transformation including new tax treaties could result in 25-35bn francs outflows over the next few years,” the bank said according to slides for the presentation.
Switzerland has struck deals with Germany, Britain and Austria to tax their citizens’ accounts without revealing their identities, which it hoped would be blueprints for other countries in Europe, including Greece and Italy.
Last year, Credit Suisse paid a fine of €150m (£120m) to end an investigation over allegations the bank and its employees helped rich Germans dodge taxes.