Moritz Kraemer, head of sovereign ratings at Standard & Poor's, said Greece will probably resort to another debt restructuring and may need an aid from official creditors such as the International Monetary Fund.

Also, he highlighted the risk of having low participation in restructuring due to the presence of preferred creditors. For the regular bond holders, the risk increases significantly. That means that the investor will demand a higher interest rate from Greece and that makes it harder for Greece and other countries on the periphery to establish a sustainable debt trajectory going forward, Kraemer said.