Tokyo - Asian shares slipped slightly in choppy trade on Thursday ahead of the US Federal Reserve's decision later in the day, but investors remained cautiously optimistic for further stimulus action to bolster the world's largest economy.
Commodities from oil to gold were also held in tight ranges ahead of the Fed decision expected to be released at 16:30 GMT, followed by Chairperson Ben Bernanke's news conference about two hours later.
A Reuters poll showed economists raised their bets of a third round of Fed bond buying known as quantitative easing (QE) to 65% from 60% in August.
As the dollar suffered from expectations for QE, which would be equal to printing money and diluting the value of the greenback, the euro stayed near four-month highs against the US currency on signs Europe was taking steps to manage its debt crisis.
European equities were seen pausing, while a 0.1% drop in US stock futures suggested a weak Wall Street start. Financial spreadbetters called London's FTSE 100, Paris's CAC-40 and Frankfurt's DAX to open little changed.
"Any goodwill towards risk assets, probably more so in FX land, could be undone pretty quickly if Ben Bernanke fails to live up to what is expected of him and the Fed board today," said Chris Weston, trader at IG Markets.
"Given the good run of equities and the fall in the USD since June, there is a real possibility (even if we get what we want) that a classic buy-the-rumour, sell-the-fact type event plays out," he said.
MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.1% after swinging in a plus and minus 0.2% range.
Australian and Shanghai shares were the worst performers, both dropping 0.4% while South Korean shares recouped earlier losses to be nearly flat.
"There's no true indication on why the market should be selling off today but they're all a bit quiet ahead of that (decision)," said Juliana Roadley, market analyst at Commonwealth Securities, of the Australian stock market.
"I think major investors just don't want to get in ahead of this major announcement," said Roadley.
Japan's Nikkei average outperformed with a 0.5% rise, buoyed by gains in shippers and Apple suppliers, amid growing expectations of an easing of US monetary conditions.
The dollar index, measured against a basket of key currencies, stuck near a four-month low and the dollar fell to a fresh three-amd-a-half month low of ¥77.68 against the yen.
"We expect the US dollar to emerge weaker both on the day and multi-day/week on delivery of QE," said Sean Callow, senior currency strategist at Westpac in Sydney.
Sluggish stocks weighed on Asian credit markets, widening the spread on the iTraxx Asia ex-Japan investment-grade index by 3 basis points, but still near its tightest level since August last year.
South Korea's central bank unexpectedly held interest rates steady at 3% on Thursday, waiting to see the effect from a eurozone bond-buying programme. Central banks in Indonesia and the Philippines also hold policy meetings this session.
German ruling boosts euro
The euro clung near its four-month high of $1.2937 touched on Wednesday, supported by positive developments in the eurozone.
Pro-European parties won a sweeping victory in Netherlands, a core eurozone country, adding to the optimism after a German constitutional court approved the eurozone's new rescue fund and budget pact, with some conditions.
The ruling is another step in a concerted effort to preserve the common currency bloc, with the European Central Bank deciding to buy short-term bonds of states that apply for bailout and abide by strict conditions, and the European Union proposing a single eurozone banking supervisor.
US crude steadied at $97.04 a barrel and Brent inched up 0.1% to $116.10.
Spot gold steadied at $1 731.54 an ounce, after expectations for a new US monetary stimulus fuelled a rally to six-and-a-half month highs of $1 746.20 on Wednesday.
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