Bank secrecy:

U.S. and Swiss law differ regarding U.S. citizens who keep accounts in Swiss banks that do business in the U.S., and an interesting game is afoot:
IRS, Justice Target Undisclosed Assets In Swiss Accounts

"Over the summer, the IRS won permission from a federal court to demand that UBS turn over the identities of an estimated 19,000 American clients who have failed to disclose their Swiss-based accounts on U.S. tax returns. It remains unclear what has or will come of that effort. Swiss law restricts the bank's ability to breach client confidentiality. Swiss law also gives clients the opportunity to oppose the release of their names through a judicial process that could slow any disclosures. "...

"James Nason, a spokesman for the Swiss Bankers Association, said, "UBS itself cannot decide to hand over client data because then it would be violating Swiss law." Any Swiss bank "waits for instructions from the Swiss authorities," Nason said, adding, "Switzerland doesn't allow fishing expeditions." ...

"Whether or not the Swiss officially give up clients' secrets, the U.S. government could have other ways of getting information. For example, bank employees have an incentive to expose tax evaders to the IRS, Skarlatos said, because whistle-blowers could receive 30 percent of the money they help the government collect. "