Actually Vito Tanzi of the IMF put it at $7 trillion; I don't know how much research when into that #.
mbs The Tax Justice Network study has drawn from data supplied by the Bank of International Settlements, Merrill Lynch and McKinsey. Richard Murphy of Tax Research, who co-authored the report, said: 'No one has tried to calculate a number like this before. To ensure the credibility of our data, we have only used information already in the public domain and produced by some of the most authoritative sources in the world.
