* Drop in Treasury yields weighs on U.S. currency
* Investors get ready for next week's Fed meeting
* 1-week implied vols for euro/dollar rise
(Adds comment, details, updates prices)
By Naomi Tajitsu
LONDON, Oct 28 (Reuters) - The dollar slipped on Thursday, relinquishing some of its gains from earlier this week as a short-covering rally ran out of steam and U.S. Treasury yields fell after a spike the previous day.
Traders said dollar selling against the euro and other currencies by reserve managers was also helping to push the U.S. currency down.
Investors trimmed extreme short dollar positions earlier this week as speculation that the Federal Reserve might announce plans to buy more assets to stimulate the economy next week turned into a guessing game about how much they would purchase.
The New York Federal Reserve has surveyed bond dealers and investors over the size and impact of a quantitative easing programme, with scenarios ranging from zero up to $1 trillion, Bloomberg news reported on Thursday, citing a copy of the survey. [
]"We'd seen a short squeeze in the dollar in the past few days due to an exhaustion in positioning, but when there's no incentive to maintain that, you get some profit taking," said Peter Frank, currency strategist at Societe Generale.
"The issue is whether the market believes the Fed will deliver significant quantitative easing over a definitive time line. If they do, the dollar will weaken."
A Reuters poll showed Wall Street analysts expect the Federal Reserve to buy $80 billion to $100 billion worth of assets per month under a new programme widely expected to be unveiled on Nov. 3. [
]"We're seeing some consolidation in the dollar before the Fed meeting as no-one knows how much QE the Fed might do," said Marcus Hettinger, global currency strategist at Credit Suisse in Zurich.
Other analysts said the dollar was also weighed down by a narrowing in spreads between 10-year U.S. and euro zone government bonds driven by a fall in U.S. Treasury yields.
By 1130 GMT, the euro <EUR=> had risen 0.6 percent on the day to $1.3849, helped by steady buying by Asian central banks. This helped to push the dollar <.DXY> 0.62 percent lower versus a currency basket.
EURO RIDES PERIPHERY CONCERNS
The euro held above a one-week low around $1.3730 hit on Wednesday, even as debt concerns in Ireland and Greece and a breakdown in budget talks in Portugal highlighted problems facing periphery euro zone countries.
Frank at SG said that support for the euro despite sovereign debt issues illustrated the resilience of the single currency, and that he expected it to rise back above $1.40 in the near term.
But worries about the banking sector and the region's debt problems could check the euro's gains. The European Central Bank's quarterly Bank Lending Survey said more banks expect to tighten their credit standards for corporate loans in Q4.
The news could check hawkish ECB intentions to scale back emergency stimulus measures, said Tom Levinson, a forex strategist at ING. "This serves as a warning on what is going on in the real economy. It's less of a positive for euro but the real dominant force is still the U.S. story."
Lingering uncertainty about how the Fed will announce more QE has increased market volatility, with one-week implied volatility for euro/dollar <EURSWO=> jumping to 15.9 percent on Thursday from 12.6 percent at the start of the week.
Against the yen, the dollar <JPY=> fell 0.6 percent to 81.26. The Japanese currency showed little reaction to a Bank of Japan decision to keep interest rates virtually at zero while holding off from new policy initiatives.
The dollar is holding above a 15-year low of 80.41 yen hit earlier this week, but investors remain vigilant for any yen-weakening intervention after authorities entered the market last month. (Additional reporting by Nia Williams; Editing by Hugh Lawson)