(Photo: ptmoney.com)At a time when the gap between the ultra-rich and the rest of us is reaching historic heights across the globe, at least $21 trillion (with a “t”) in unreported private financial wealth was recently discovered sitting in secret tax havens.

While it can be difficult to imagine sums so large, consider this: the $21 trillion alone is the amount of the U.S. and Japanese economies combined. That reflects only financial wealth, and not the holdings and investments of this monied elite in mansions, yachts, private jets, etc. According to a recent reports by the Tax Justice Network, “The Price of Offshore Revisited” and “Inequality: You Don’t Know The Half of It,” this staggering disparity is only growing worse.

The report states at the end of 2010, the wealthiest fifty private banks held over $12.1 trillion, up $5.4 trillion from 2005. Three private banks handle the lion’s share of offshore assets — UBS, Credit Suisse, and Goldman Sachs. If these offshore holdings earned a very modest 3% return rate, and the income were to be taxed at 30%, this would generate tax revenues between $190 – $280 billion.

The study is one of the first attempting to measure the hidden wealth. It could be as high as $32 trillion — a staggering sum.

At a time when governments around the world are starved for resources, and we are more conscious than ever of the costs of economic inequality, “This new report focuses our attention on a huge ‘black hole’ in the world economy that has never before been measured — private offshore wealth, and the vast amounts of untaxed income that it produces,” says the author James Henry, who is the former chief economist of the global management firm, McKinsey & Company.