Quote from jficquette:
"WASHINGTON -- In 2006 and 2007, Goldman Sachs Group peddled more than $40 billion in securities backed by at least 200,000 risky home mortgages, but never told the buyers it was secretly betting that a sharp drop in U.S. housing prices would send the value of those securities plummeting."
http://www.miamiherald.com/509/story/1310367.html
GS didn't have the market cornered on betting against the housing market.