The IRS got court orders permitting it to see information about taxpayers with undisclosed offshore bank accounts from US banks. In re the Tax Liabilities of John Does (SDNY No. 1:13-mc-00377 Nov. 12, 2013).
According to BNA Daily Tax RealTime (Nov. 12, 2013 5:59pm), these orders will apply to Bank of New York Mellon, Citibank NA, JPMorgan Chase Bank NA, HSBC Bank USA NA, and Bank of America NA. Those banks will be "required to produce information about U.S. taxpayers with undisclosed accounts at the Bank of N.T. Butterfield & Son Ltd. and its affiliates. The Butterfield bank operates in the Bahamas, Barbados, Cayman Islands, Guernsey, Hong Kong, Malta, Switzerland, and the U.K."