S&P downgrades U.S. agencies' debt

Officials at Standard & Poor's are downgrading the credit ratings of mortgage lenders Fannie Mae and Freddie Mac and other agencies linked to long-term U.S. debt.

The agency says it has also lowered the ratings for farm lenders; long-term U.S. government-backed debt issued by 32 banks and credit unions, and three major clearinghouses, which are used to execute trades of stocks, bonds and options.

All the downgrades were from AAA to AA+. S&P says the agencies and banks all have debt that is exposed to economic volatility and a further downgrade of long-term U.S. debt.

Officials at Standard & Poor's say they will also indicate shortly how local and state governments will be affected by their decision on Friday to lower the long-term U.S. debt from AAA to AA+.