The McKinsey Global Institute recently estimated that world financial assets today are more than three times world GDP – triple the ratio in 1980 (and up from only two-thirds of world GDP after World War II). And then there are the numbers that sound very large and are hard to interpret: $300 trillion in “derivative” securities; $3 trillion managed by 12,000 global “hedge funds”; $1.2 trillion a year in “private equity.”