Following its downgrade of the U.S. government’s credit rating, Standard & Poor’s has now downgraded Fannie Mae and Freddie Mac, saying in a statement, “The downgrades of Fannie Mae and Freddie Mac reflect their direct reliance on the U.S. government.”

Moody’s — the other major rating agency — had listed the U.S. as “review for downgrade,” but on August 2 removed that note and reaffirmed the federal government’s AAA rating. It does, however, have a “negative outlook” for the rating.

As CNBC explained,

If the United States manages to keep its AAA rating until the end of 2012, Moody’s will likely take into account how the government will handle the expiration of Bush-era tax cuts to make a decision on the AAA rating…