Asian stocks and the euro firmed on Wednesday, as investor risk appetite returned after upbeat U.S. and European economic data boosted global shares and commodities and hopes for improved growth outlook grew despite worries over the euro zone debt crisis.

MSCI's broadest index of Asia Pacific shares outside Japan was up 0.6 percent. The index fell 18 percent in 2011, sharply underperforming Wall Street's S&P 500 which ended the year virtually unchanged.

Japan's Nikkei stock average opened up 1.11 percent.

On Tuesday, European stocks closed at their highest in five months while U.S. stock indexes hit multi-month highs.

While we are structurally underweight risk, we suggest adopting a more neutral stance in the first two weeks of 2012, analysts at Barclays Capital said in a research note.

We do not expect higher risk premia because risky assets have sold off to a point where they offer interesting excess returns and because it has become expensive to short risk further unless data consistently surprise on the downside.

The euro held steady around $1.3050 after posting its biggest one-day rally in nearly two months and reached a one-week high of $1.3077 the previous day on upbeat data, staying well above its 2011 low of $1.2856 hit on December 29.

The single currency was also up against the yen at 100.14 yen, off a trough of 98.71 hit on Monday, its lowest since late 2000.

Oil prices remained underpinned by data suggesting demand from the world's two largest economies, the United States and China, may remain strong. Supply disruption concerns from Iran, which has threatened to cut off crude oil shipments through the strategic Strait of Hormuz as Tehran rebukes the sanctions imposed by the West over its nuclear programme, also helped.

U.S. manufacturing grew at its fastest pace in six months in December while U.S. construction rose to a near 1-1/2-year high in November, and German unemployment fell sharply to the lowest in two decades.

These data followed earlier figures showing Chinese manufacturing and service data topping forecasts, and the euro zone's purchasing managers index contracting less than it had been feared.

A key focus this week is the U.S. employment data due on Friday, with analysts forecasting 150,000 jobs added in December, up from 120,000 in November.

Analysts say global economic data and European events will continue to drive markets in 2012, and that investors were expected to remain wary of aggressively taking risks throughout the year.

We expect global economic concerns to begin to dominate as Q1 2012 progresses, Standard Chartered said in a note to clients.

The analysts at Barclays Capital said they would recommend being structurally short the EUR, underweight currencies that are sensitive to European risks, and tactically going neutral (from underweight) risky currencies during times when risk sentiment temporarily improves.

Risks related to the euro zone debt crisis include progress in Greece's fiscal reforms, Italy's refinancing of about 150 billion euros ($195.8 billion) of government debt in February-April alone and the possibility of sovereign credit rating cuts in key euro zone economies including France.

Other risks are the development in safety nets for Europe's bailout funds and other schemes to prevent euro zone countries from defaulting on their huge debts as they face market scrutiny which puts strong upward pressures on their borrowing costs.

Possible actions from the European Central Bank to expand its role in helping resolve the debt crisis and regulations to ensure that banks hold adequate capital are also market movers.

($1 = 0.7661 euros)

(Editing by Yoko Nishikawa)