Greece’s credit ratings were cut to the lowest level by Moody’s Investors Service late on Friday after the country negotiated the biggest sovereign debt restructuring ever.

Moody’s dropped Greece’s rating to C from Ca, saying in a statement that investors who participate in the nation’s debt exchange will get about 70 percent less than the face value of their holdings. The deal constitutes “a distressed exchange, and hence a default,” the New York-based rating company said.

The downgrade follows Standard & Poor’s decision on Monday to lower Greece to «selective default» after the announcement of the plan for investors to trade their bonds for new securities. The swap will reduce Greece’s 200 billion euros of privately-held debt by about half if all investors participate.

Greece negotiated the restructuring as it seeks to reduce national debt to 120 percent of gross domestic product by 2020, from 160 percent last year, and to meet the terms of a 130-billion-euro international bailout.

The country faces a high risk of default even if the plan is successful, Moody’s said. It will be unlikely to be able to sell bonds to private investors once its bailout package runs out, according to the rating company.