Credit rating agency Moody's has downgraded Japan's sovereign debt rating by one notch, saying weak political leadership has hampered growth.
Leading ratings agencies have re-affirmed the US' AAA-rating following the last gasp deal to approve an increase in its debt ceiling.
Moody's has placed Spain's Aa2 government bond rating on review for a potential downgrade over concerns the new bailout package for Greece will increase risks for bondholders.
Cyprus is the latest nation to be slapped with a downgrade by Moody's, with its rating cut two notches over concerns the country is heading towards a bailout.
Moody's ‘red flag' corporate governance report casts shadow over Chinese companies.
The Federal Reserve chairman Ben Bernanke has ramped up pressure on Congress to agree on its debt ceiling level, in light of rating agencies S&P's and Moody's threats to cut the US' triple-A debt rating.
Ratings agency Moody's has said it may cut the US AAA debt rating, pointing to the "rising possibility" the US will default on its debt obligations.
The FTSE 100 fell below the 6,000 level in mid-morning trading as European markets absorbed Moody's downgrade of Portuguese debt to 'junk' status.
Moody's has downgraded Portuguese debt to 'junk' status on fears it will need a second bail out just months after it received €78bn.
Three major French banks could have their credit ratings cut by Moody's because of their exposure to Greek debt.