I seem to recall the government nationalizing Fannie and Freddie thereby making good on their implicit guarantee of the two firm's debt, and insuring that holders of their CDOs would remain whole. Just in case you're curious, Fannie and Freddie aren't giveaway programs. They securitize mortgages and back the securities and prior to the nationalization, they were private firms. Fannie and Freddie's problem is that the market understood their debts to be implicitly backed by the Federal Government, which allowed them to borrow at extremely low interest rates, and get away with very thin asset cushions which mean the moment the crisis hit, they quickly went insolvent.

The truly toxic crap was securitized and sold by Wall Street. They gobbled up and securitized the sub prime sludge that was too poisonous for Fannie and Freddie to touch. They bundled it, sliced it into tranches, got the rating agencies to slap triple-A ratings on as large a slice as they could and sold it and the other tranches to investors. In many cases they kept the riskiest, but potentially most lucrative tranches on their own balance sheets. As a result, many of the nations largest banks suffered huge losses and their are no longer any massive pure investment banks in this country. It's Wallstreet, not Fannie and Freddie that enabled the worst excesses of the housing bubble by securitizing the worst of the loans. Then they went out and magnified the problem by creating a $40 trillion mound of CDS, synthetic CDOs and other derivatives tied to the housing bubble.