The single currency jumped more than 1 euro cent on Wednesday to a high of $1.2625 after a string of leaks from euro zone officials raised expectations that the ECB will unveil a bond intervention plan after Thursday's policy meeting.
"This meeting is absolutely crucial, because expectations are extremely high. If the ECB does not deliver, we will get into another bad patch," said Gilles Moec, senior European economist at Deutsche Bank.
The euro held steady just below $1.26 on Thursday and the dollar was flat against a basket of major currencies.
MSCI's broadest index of Asia Pacific shares outside Japan rose 0.2 percent while Japan's Nikkei was flat.
U.S. stocks had largely ignored the European news, with the Dow Jones Industrial Average gaining 0.1 percent but the broader S&P 500 easing 0.1 percent, hurt by a profit warning from economic bellwether FedEx Corp.
"While FedEx is only one company, it's one whose warning is indicative of the global economic slowdown we're dealing with," said Leo Grohowski, chief information officer at BNY Mellon Wealth Management in New York.
Oil was boosted by expectations that ECB action will support asset prices, with U.S. crude up 0.4 percent at $95.78 a barrel and Brent crude gaining 0.3 percent to $113.44.
But gold edged back from near a six-month high, easing around $1.50 to about $1,691.50 an ounce.
Copyright Thomson Reuters 2012