On Tuesday, the euro and global shares eased while safe-haven German government bonds rose as demand for riskier assets stalled after ratings agency Moody's downgraded some countries of Europe.

The Central Bank of Japan surprised markets with a further loosening of the monetary policy by increasing its asset buying and lending scheme. The bank's move tallies with easing by other major central banks that encouraged investors to move into riskier assets like equities.

The single currency, euro, fell 0.3 percent to $1.3147 and the FTSEurofirst index of top European companies opened down 0.2 percent after the AAA ratings of France, Britain, and Austria were cut by Moody's that also downgraded Italy, Portugal, Spain, Slovakia, Slovenia and Malta.

"Clearly this was not a game changer, but comes at a time when risk assets are in reflection mode after a strong run," Chris Weston, institutional trader at IG Markets, said.

A barometer for Europe's lower-rated sovereigns, Italian 10-year yields, rose slightly to 5.64 percent with investors eyeing the 25 billion euros of new euro zone supply this week, with Italy, France, and Spain all looking to sell bonds. German government bond futures were 39 ticks higher at 138.62 with 10-year yields 3.5 basis points lower at 1.899 percent.