Standard and Poor's reaffirmed its rating on Japan's sovereign debt at AA minus and kept its outlook negative on Monday, Feb 20, saying that structural problems such as shrinking nominal gross domestic product and increasing social security costs are weighing on the country's ability to reduce its budget deficit, Reuters reported.

S&P cut France's and Austria's top ratings and downgraded seven other euro zone nations last month. It also cut the euro zone's bailout fund by one notch.

Moody's also cut the ratings of six European nations including Italy, Spain and Portugal and warned it could strip France, Britain and Austria of their top-level AAA grade.

Besides, the agency downgraded the insurance financial strength ratings (IFSR) by one or two notches of several insurance companies, which it said related to their investment and operating exposures to Spain and Italy.