Upgrade driven rally du matin An upgrade in this environment is apparently stupidly effective. Here's Greece's 10-year bond yield tumbling a full one per cent the day after Fitch upgraded it to to B- from CCC, and said the outlook was stable: Here's the FT explaining the move: "The price has been high in terms of lost output and rising unemployment, and the capacity for recovery is still in doubt," Fitch said in a statement. Nonetheless, sovereign debt relief and an easing of fiscal targets have lifted central bank measures of economic sentiment to a three-year high and the risk of eurozone exit has receded. Nonetheless, many economists and investors say Greece will again have to restructure its debts, which Fitch estimates will hit 180 per cent of GDP in 2013-14. "Public debt sustainability is still far from assured and will be dependent on economic recovery and a sustained primary fiscal surplus," the rating agency said. But the burden of any further debt reductions is expected to fall more heavily on the eurozone's official sector than on private investors, who represent only 15 per cent of Greece's debt burden. And the longer view to really drive this rally home: