NEW YORK ( TheStreet) -- Greece's private creditors may have agreed to a debt exchange swap with the struggling country but that doesn't mean Moody's has to like the deal. The ratings agency lowered its rating on Greece's local- and foreign-currency bond ratings to its lowest rating of C from Ca and didn't assign an outlook for the ratings because it still sees a "very high likelihood" that the country will default. "The announced debt exchange proposal implies that private creditors that participate will incur substantial economic losses on their holdings of Greek government debt," the agency said in a statement. "Moody's estimates that the percentage difference between the value of the coupon and principal promised by existing Greek government bonds and the value of the package investors will receive in the exchange exceeds 70%, which is consistent with a C rating." There are still many details to be worked out with this debt swap and the conditions being set by Eurozone leaders for Greece to receive its next round of bailout monies, though the parameters of a deal have already been laid out. Moody's expects more clarity on the debt swap early this month when the exchange is executed, but it's got plenty of big-picture reservations. "Looking ahead, the EU programme and proposed debt exchanges will reduce Greece's debt burden, but the risk of a default even after the debt exchange has been completed remains high," the agency said. "Moody's believes that Greece will still face medium-term solvency challenges: its stock of debt will still be well in excess of 100% of GDP for many years; the country is unlikely to be able to access the private market once the second assistance package runs out; and its planned fiscal and economic reforms will still face very significant implementation risks. U.S. stocks haven't been hampered by the debt problem in Europe in 2012 with the Dow Jones Industrial Average rising 6.2%; the S&P 500 advancing nearly 9%, and the Nasdaq Composite soaring 14.2%. -- Written by Michael Baron in New York. >To contact the writer of this article, click here: Michael Baron.