Who led the subprime loans?

Countrywide was a growing force in the mortgage industry when it partnered with Fannie in 1992. But after Mozilo's firm secured a steady government buyer for their loans, business exploded. Revenues went from $92 million in 1992, to $860 million in 1996, to $2 billion in 2000. By 2004, they were the nation's largest mortgage lender.

The secret to Countrywide's success was no mystery: They shredded standard industry lending practices, giving home loans to virtually anybody who asked. Fannie Mae not only knew this, Fannie rewarded it.

In 2000, the Fannie Mae Foundation honored Countrywide for "Outstanding Achievement" in the industry. The foundation's 2000 annual report noted: "When necessary -- in cases where applicants have no established credit history, for example -- Countrywide uses nontraditional credit, a practice now accepted by [Fannie]."

Countrywide continued to be the biggest supplier of loans to Fannie Mae all the way through the height of the housing boom. In 2004, 26 percent of the loans Fannie bought were from Countrywide. In 2007, that number had risen to 28 percent.

In his 1993 Nobel Prize lecture, economist Douglass North said, "If the institutional framework rewards piracy, then piratical organizations will come into existence; and if the institutional framework rewards productive activities then organizations -- firms -- will come into existence to engage in productive activities."

From 1992 through the height of the housing bubble, Fannie Mae and Freddie Mac used their monopoly position in the mortgage securitization industry to reward firms like Countrywide for making bad bets in the housing market. Countrywide's success was a signal to other market participants to lower their standards as well.

Wall Street banks are not blameless for the financial crisis. But they were only responding to the incentives set up by the federal government.