According to a major study the global super-rich elite had at least $21 trillion hidden in secret tax havens by the end of 2010.
The figure is equivalent to the size of the US and Japanese economies combined.
The Price of Offshore Revisited was written by James Henry, a former chief economist for the UK Tax Justice Network.
Henry used data from the Bank of International Settlements, International Monetary Fund, World Bank, and national governments.
His study deals only with financial wealth deposited in bank and investment accounts, and not other assets such as property.