By the peak of the housing boom in 2006, Goldman was underwriting $76.5 billion worth of mortgage-backed securities a third of which were sub-prime much of it to institutional investors like pensions and insurance companies. And in these massive issues of real estate were vast swamps of crap.
Take one $494 million issue that year, GSAMP Trust 2006S3. Many of the mortgages belonged to second-mortgage borrowers, and the average equity they had in their homes was 0.71 percent. Moreover, 58 percent of the loans included little or no documentation no names of the borrowers, no addresses of the homes, just zip codes. Yet both of the major ratings agencies, Moody's and Standard & Poor's, rated 93 percent of the issue as investment grade. Moody's projected that less than 10 percent of the loans would default. In reality, 18 percent of the mortgages were in default within 18 months.
Not that Goldman was personally at any risk. The bank might be taking all these hideous, completely irresponsible mortgages from beneath-gangster-status firms like Countrywide and selling them off to municipalities and pensioners old people, for God's sake pretending the whole time that it wasn't grade D horseshit. But even as it was doing so, it was taking short positions in the same market, in essence betting against the same crap it was selling. Even worse, Goldman bragged about it in public. "The mortgage sector continues to be challenged," David Viniar, the bank's chief financial officer, boasted in 2007. "As a result, we took significant markdowns on our long inventory positions
However, our risk bias in that market was to be short, and that net short position was profitable." In other words, the mortgages it was selling were for chumps. The real money was in betting against those same mortgages.