Standard and Poor's said on Monday it lowered Greece's CC long-term and C short-term sovereign credit ratings to Selective Default or SD after the debt-swap deal reached with private sector bondholders last week which includes write down worth 53.5%.

S&P said In our opinion, Greece's retroactive insertion of CACs materially changes the original terms of the affected debt and constitutes the launch of what we consider to be a distressed debt restructuring.

We believe that the retroactive insertion of CACs will diminish bondholders' bargaining power in an upcoming debt exchange, S&P added.

S&P also clarified that if the swap is completed, we will likely consider the selective default to be cured and raise the sovereign credit rating on Greece to the 'CCC' category, reflecting our forward-looking assessment of Greece's creditworthiness.