The New York Times has a story reviewing developments in the private banking industry. The article notes a couple of important points. First, high-tax nations - and the international bureaucracies that represent those nations - resent Swtizerland for serving as a refuge:

For generations, Europe’s wealthy journeyed through mountains and valleys to quietly stash their money with Switzerland’s bankers, famed for taking their secrets to the grave. …many of the country’s detractors complain that Switzerland remains the world’s prime tax haven. The European Union and the Organization for Economic Cooperation and Development have pressured Switzerland to loosen its bank secrecy.

Second, the article notes that high-tax countries can get at least some money to return home if they remove and/or reduce the tax penalites:

Several countries, including Italy and Belgium, have lured back untaxed assets held abroad by decreeing an amnesty for tax evasion. But that is not the biggest challenge.

Third, tax competition is creating other havens for people seeking to avoid not only punitive taxes, but also other forms of oppression:

As Swiss bankers penetrate markets abroad they are facing like-minded competitors from elsewhere in the world. Dubai and Singapore have cultivated sophisticated private banking hubs, offering discreet financial services and a tax haven aimed at luring away wealthy clients. And just as the Swiss have moved overseas, foreign banks like Citibank have flocked to Switzerland. Geneva, once a sleepy lakeshore town, now has branches of 100 foreign banks.

Lastly, the article notes that Switzerland has a completely different approach from America. Unlike the US - which has a so-called Bank Secrecy Act that strips away financial privacy, Swtizerland still respects the fundamental right to privacy. Citizens are treated like adults - a relationship that is facilitated by a better tax regime:

Unlike regulations in the United States, Swiss law forbids bankers from divulging information about clients or their assets, under threat of penalty. Tax evasion is not considered a crime.