But the point of both articles is that these groups are not even unified within themselves, much less can they collude effectively, or out-maneuver the various forces that would not want them to control everything. And even if they could - what then? Managing even one company is difficult, trying to coordinate several thousand is essentially impossible.
More pedantically, you're assuming those groups could take all of those assets from where the owners of those assets put them (including bonds, commodities, foreign investments, etc) and put them into the US stock market. Even if they did so they're barely above 50% of the US market cap (put at 25 trillion by World Bank).
You are not counting effects of circular ownership citi owns 5% of Chase and Chase owns 5% of Citi and on and on you effectively don't need 50% to control the vote. Even if those 4 are off you can add next two or three with trillion +/- under management. So worst case you need 7 people to collude.
More pedantically, you're assuming those groups could take all of those assets from where the owners of those assets put them (including bonds, commodities, foreign investments, etc) and put them into the US stock market. Even if they did so they're barely above 50% of the US market cap (put at 25 trillion by World Bank).
http://data.worldbank.org/indicator/CM.MKT.LCAP.CD?locations...