The nation has offered 10 billion euros ($13.1 billion) to buy back bonds issued earlier this year as the bailed-out country attempts to cut a debt load that may threaten future international aid. The nation’s rating was lifted to CCC from SD in May after undergoing the largest sovereign restructuring in history.

The buyback invitation issued by Greece “constitutes the launch of what we consider to be a distressed debt restructuring,” S&P said in a statement. “Any potential upgrade to the CCC category rating would reflect, among other factors, our view of the debt relief that is being delivered through the buy back and its contribution to putting the sovereign’s public finances on a sustainable footing.”

Greece began repurchasing of bonds maturing from 2023 to 2042 this week, offering a higher-than-planned price in order to increase demand for the debt-reduction measure.

The SD designation “includes the completion of a distressed exchange offer, whereby one or more financial obligation is either repurchased for an amount of cash or replaced by other instruments having a total value that is less than par,” according to S&P’s website.