The headquarters of mortgage lender Fannie Mae is shown in Washington September 8, 2008.JASON REED/Reuters
Standard & Poor's cut Freddie Mac and Fannie Mae's long-term ratings one notch on Monday.
S&P said the downgrades from the top-notch Triple-A were due to its lowering of the U.S. sovereign credit rating late on Friday.
"The downgrades of Fannie Mae and Freddie Mac reflect their direct reliance on the U.S. government," the rating agency said.