Swiss bankers will have to market the country's stability and expertise as selling points after an agreement with US authorities over UBS accounts effectively ended Switzerland's days as a tax haven.

Swiss bank secrecy remains only in name after the deal to disclose details of about 4,450 wealthy American clients of UBS to US authorities on Wednesday, removing a major advantage for the country's wealth managers.

"This is a major victory for the US," said Fox-Pitt Kelton analyst David Williams in London. "Bank secrecy is dead."

Swiss National Bank data from May said Swiss banks held around 2.9 trillion Swiss francs ($2.7 trillion) in assets, and 3.9 trillion francs in custody accounts including 1.1 trillion francs held for private clients.

With bank secrecy compromised, the size of the Swiss financial industry could be cut to between 6 per cent and 7 per cent of the gross domestic product from 12 per cent, private banker Ivan Pictet has said.

That means the Swiss will now have to flaunt the Alpine country's economic and political stability to capture new clients in markets where finding a safe haven for your money is more urgent than dodging the taxman.

"Secrecy is only one attraction of the Swiss banking place among others such as the country's low debt, low inflation and a currency that did not have to be reformed even in the 1930s," said Boris Zuercher, head of economic policy at think tank Avenir Suisse.

Most assets held by Swiss private banks belong to citizens of the European Union, which would soon take similar action to the United States, Fox-Pitt Kelton's Williams said.

Swiss banks will also need to prove their much-vaunted expertise to continue attracting clients, especially as authorities outside the United States look to crack down on citizens with money stashed away in secret accounts.

Expertise crucial

The Swiss government decided the agreement drew enough of a line under UBS's problems for it to exit from its investment in the bank, but the deal could open the floodgates for voluntary disclosure of accounts by other Swiss private banking clients fearful of being tracked down by tax authorities.

The Wall Street Journal has reported that the US taxman may now look closely at other Swiss banks, such as Credit Suisse , Julius Baer, Zuercher Kantonalbank (ZKB) and Union Bancaire Privee (UBP).

Stephane Garelli, professor of international business policy at Lausanne University, said smaller financial institutions that have lived exclusively on specific aspects of Swiss law and have nothing else to offer would suffer most.

"Other institutions which have a long established business providing a variety of services such as investment advice, trading, succession planning and trust services will probably fare much better," Garelli said.

Switzerland's banking industry had accumulated competencies, professionalism and a very large base of customers in a history going back over 200 years and this would not disappear overnight, he said.

"Many banks around the world are successful because quality of service and stability and durability makes them attractive. Switzerland can provide all that," Garelli added.

Banks bow to pressure

Private banking sources said many banks closed their doors to new US clients altogether as the UBS case dragged on. Some told existing clients to find a new bank, while others significantly raised disclosure requirements for US clients.

"The decision will provide a useful roadmap for obtaining US taxpayer information from other Swiss financial institutions and will likely be tailored to target institutions in other jurisdictions," said Jay Krause, partner at international law firm Withers.

Peter Hardy, a former US Federal Prosecutor and specialist in white-collar crime at Post & Schell in Philadelphia, also thinks there is plenty more to come.