Standard & Poor's said Tuesday it had upgraded Greece's sovereign credit rating to CCC+ from CCC-. The ratings firm also revised the country's outlook to stable from negative.
S&P said it believes the possibility of Greece leaving the euro zone by 2018 (a so-called Grexit) has fallen to less than 50 percent, but the risk "is still high."
The Greece upgrade reflects the "improved liquidity perspective" after the country reached a deal in principle with some of its creditors, S&P said.
In fact, after clearing arrears with the International Monetary Fund and making a repayment to the European Central Bank, a Greek default on its stock of commercial debt "is no longer inevitable in the next six to 12 months," the ratings agency said.
Still, Greece's commitments may be "unsustainable" in the long term, S&P said, adding that the chances of a Grexit remain higher than one in three.