Moody's Investors Service has cut Greece's soverign-debt rating to the lowest level possible just short of a default.

The ratings agency says it downgraded the debt-ridden nation's rating from 'Ca' to 'C' on Friday after it was learned that Greece's debt-restructuring deal imposes substantial economic losses for private creditors on their holdings of government debt.

Moody's did not offer a ratings outlook on Greece after the debt-ridden country agreed to the deal.