Excerpt: The fallout from the nation's credit downgrade continued Monday, as Standard & Poor's announced government-sponsored housing giants Fannie Mae and Freddie Mac were also getting their top rating slashed. The two government-sponsored enterprises saw their credit rating from S&P fall from AAA to AA+ after the rater dropped the nation's rating to the same level on Friday. Fannie and Freddie back roughly 90 percent of all new mortgages created in the United States.