The Wall Street Journal has an investigative piece outlining how Goldman Sachs Fueled AIG Gambles. It appears Goldman Sachs acted as a middleman for even more CDSes from other banks.

Goldman originated or bought protection from AIG on about $33 billion of the $80 billion of U.S. mortgage assets that AIG insured during the housing boom. That is roughly twice as much as Société Générale and Merrill Lynch, the banks with the biggest exposure to AIG after Goldman.

In Goldman's biggest deal, it acted as a middleman between AIG and banks, taking on the risk of as much as $14 billion of mortgage-related investments. Then Goldman insured that risk with one trading partner—AIG, according to the Journal's analysis and people familiar with the trades.