Credit ratings agency Standard & Poor's has raised Greece's  sovereign long-term credit rating from selective default to a "B-" and also raised its short-term outlook on Greece from default to a "B." S&P cited the completion of Greece's debt buyback plan along with the approval of eurozone loans to Greece as being main drivers in the upgrade. Last week, officials from the eurozone approved a further $65 billion worth of loans to Greece through March.

S&P cut Greece's rating to "selective default" from a "CCC" on Dec. 5 during the debt buyback, although the nation hasn't had a credit rating this high since mid-2011.

While the agency noted that Greece's significant public debt remains  problematic, it states that eurozone nations have agreed to improve loan terms should Greece successfully meet lending stipulations. S&P believes economic contraction could continue through 2012 and 2013 in the nation.

The agency also noted that it could raise Greece's long-term rating higher in the future if the nation fully meets bailout conditions laid out by the European Union and International Monetary Fund.