The number of American taxpayers reporting foreign accounts to the Internal Revenue Service (IRS) doubled to 516,000 between 2007 and 2010, according to the US Congress' General Audit Office (GAO).

The GAO investigation also found that 6 per cent of US taxpayers who took up the IRS' 2009 offshore tax amnesty received penalties of USD1 million or more, and most of them had accounts at the Swiss bank UBS.

 Sources:
GAO statement

GAO Report (PDF file)

Reuters