Standard Poor's has warned that six euro zone countries rated AAA may be downgraded in the next 90 days.
The Financial Times reports that the agency is poised to announce that the credit ratings of Germany, France, the Netherlands, Austria, Finland and Luxembourg - are in credit watch negative.
That means there is a 50% chance of a downgrade from the agency.
The BBC says the move would be a surprise to the markets which saw strong gains earlier on Monday.
SP refused to comment on the reports.