Moody's calls a rating of "C" a bond in default. Greek bonds, Moody's said, are now at a "Ca" rating, a drop from the previous "Caa1" rating, CNNMoney.com reported.
All of those ratings fall under the umbrella of junk bonds, which covers the grade categories below a recommended investment.
Moody's said the second bailout package for Greece approved last week "carries a number of benefits for Greece -- a slightly reduced debt trajectory, lower debt-servicing costs, as well as reduced reliance on financial markets for years to come."
However, Moody's said, "The impact on Greece's debt burden is limited."