A global super-rich elite has exploited gaps in cross-border tax rules to hide an extraordinary £13 trillion ($21tn) of wealth offshore – as much as the American and Japanese GDPs put together – according to research commissioned by the campaign group Tax Justice Network.

James Henry, former chief economist at consultancy McKinsey and an expert on tax havens, has compiled the most detailed estimates yet of the size of the offshore economy in a new report, The Price of Offshore Revisited, released exclusively to the Observer.

He shows that at least £13tn – perhaps up to £20tn – has leaked out of scores of countries into secretive jurisdictions such as Switzerland and the Cayman Islands with the help of private banks, which vie to attract the assets of so-called high net-worth individuals.

Oil-rich states with an internationally mobile elite have been especially prone to watching their wealth disappear into offshore bank accounts instead of being invested at home, the research suggests. Once the returns on investing the hidden assets is included, almost £500bn has left Russia since the early 1990s when its economy was opened up. Saudi Arabia has seen £197bn flood out since the mid-1970s, and Nigeria £196bn.

"The problem here is that the assets of these countries are held by a small number of wealthy individuals while the debts are shouldered by the ordinary people of these countries through their governments," the report says.

The sheer size of the cash pile sitting out of reach of tax authorities is so great that it suggests standard measures of inequality radically underestimate the true gap between rich and poor. According to Henry's calculations, £6.3tn of assets is owned by only 92,000 people, or 0.001% of the world's population – a tiny class of the mega-rich who have more in common with each other than those at the bottom of the income scale in their own societies.

Assuming the £13tn mountain of assets earned an average 3% a year for its owners, and governments were able to tax that income at 30%, it would generate a bumper £121bn in revenues – more than rich countries spend on aid to the developing world each year.

http://www.guardian.co.uk/business/2012/jul/21/global-elite-tax-offshore-economy

http://www.taxjustice.net/cms/front_content.php?idcat=148