Wealth doesn't trickle down – it just floods offshore, new research reveals

A far-reaching new study suggests a staggering $21tn in assets has been lost to global tax havens. If taxed, that could have been enough to put parts of Africa back on its feet – and even solve the euro crisis

The world's super-rich have taken advantage of lax tax rules to siphon off at least $21 trillion, and possibly as much as $32tn, from their home countries and hide it abroad – a sum larger than the entire American economy.

Using the BIS's measure of "offshore deposits" – cash held outside the depositor's home country – and scaling it up according to the proportion of their portfolio large investors usually hold in cash, he estimates that between $21tn (£13tn) and $32tn (£20tn) in financial assets has been hidden from the world's tax authorities.

"These estimates reveal a staggering failure," says John Christensen of the Tax Justice Network.

"This new data shows the exact opposite has happened: for three decades extraordinary wealth has been cascading into the offshore accounts of a tiny number of super-rich."

In total, 10 million individuals around the world hold assets offshore, according to Henry's analysis; but almost half of the minimum estimate of $21tn – $9.8tn – is owned by just 92,000 people. And that does not include the non-financial assets – art, yachts, mansions in Kensington – that many of the world's movers and shakers like to use as homes for their immense riches.