Ratings agency Standard & Poor's has placed the credit ratings of 15 Euro Zone nations on review for possible downgrade. Germany and France, the Euro Zone's two largest economies, could lose their AAA credit ratings. That pair along with 13 other countries are on credit watch negative, which means S&P could move to downgrade the ratings in three months or less. Austria, Finland, Luxembourg and the Netherlands are also among the AAA nations that could be downgraded. S&P said ratings could be pared "up to one notch for Austria, Belgium, Finland, Germany, Netherlands and Luxembourg, and by up to two notches for the other governments,” including France. Moody's Investors Service and Fitch Ratings have previously warned they might downgrade some of the Euro Zone's AAA members. The U.S. lost its AAA credit rating in August.