Fannie Mae had stopped buying Alt-A products in the early 1990s because of the high risk of default. By 2008, the Fannie Mae and Freddie Mac owned, either directly or through mortgage pools they sponsored, $5.1 trillion in residential mortgages, about half the total U.S. mortgage market.
From your own quote. Notice that yes, they did own about half the mortgages, but what percentage of them were sub-prime? Answer:
"Start with the most basic fact of all: virtually none of the $1.5 trillion of cratering subprime mortgages were backed by Fannie or Freddie. That’s right — most subprime mortgages did not meet Fannie or Freddie’s strict lending standards. All those no money down, no interest for a year, low teaser rate loans? All the loans made without checking a borrower’s income or employment history? All made in the private sector, without any support from Fannie and Freddie.
Look at the numbers. While the credit bubble was peaking from 2003 to 2006, the amount of loans originated by Fannie and Freddie dropped from $2.7 trillion to $1 trillion. Meanwhile, in the private sector, the amount of subprime loans originated jumped to $600 billion from $335 billion and Alt-A loans hit $400 billion from $85 billion in 2003. Fannie and Freddie, which wouldn’t accept crazy floating rate loans, which required income verification and minimum down payments, were left out of the insanity."
Fannie Mae and Freddie Mac were victims, not culprits - BusinessWeek
"Federal Reserve Board data show that:
More than 84 percent of the subprime mortgages in 2006 were issued by private lending institutions.
Private firms made nearly 83 percent of the subprime loans to low- and moderate-income borrowers that year.
Only one of the top 25 subprime lenders in 2006 was directly subject to the housing law that's being lambasted by conservative critics.
The "turmoil in financial markets clearly was triggered by a dramatic weakening of underwriting standards for U.S. subprime mortgages, beginning in late 2004 and extending into 2007,"
Read more here: http://www.mcclatchydc.com/2008/10/12/53802/private-sector-loans-not-fannie.html#storylink=cpy"