CNN: S&P Downgrades Fannie Mae and Freddie Mac

Following on the heels of their credit rating downgrade for the U.S. government late Friday, Standard and Poor's on Monday downgraded government-backed mortgage financers Fannie Mae and Freddie Mac from AAA to AA+, CNN reports.

The rating agency said the companies were downgraded because they are so closely tied to the U.S. government's debt. A downgrade typically makes it more expensive to borrow money, but investors leery of debt crises in Europe and elsewhere still flocked to U.S. Treasury yields Monday, driving them down.