* Dlr/yen capped by expectations for Japan exporter selling
* Dollar may extend gains on short-term buying
* But data shows dollar shorts at lowest in 10 months
By Satomi Noguchi
TOKYO, Dec 21 (Reuters) - The dollar held firm on Monday near its highest point in more than three months against the euro as currency players anticipated more short-covering in the greenback until the Christmas break later this week.
A brighter outlook for the U.S. economy after stronger figures on the job market and retail sales earlier this month has also helped the dollar maintain its rising momentum.
The euro remained vulnerable after the European Central Bank raised its estimate of euro zone bank writedowns, while ECB governing council member Ewald Nowotny said European governments should not withdraw special support for their banks too early.
"The dollar may extend gains a little more as momentum buyers could chase the dollar up while it stays in an uptrend," said Masafumi Yamamoto, chief FX strategist for Barclays Capital in Japan.
"But gains are likely to slow down, unlike what we saw last week, because many dollar-short positions have already been neutralised by now, and short positions in the euro on the other hand are growing," Yamamoto said.
Speculators cut bets against the dollar to their lowest level in more than 10 months in the week ended Dec. 15, Commodity Futures Trading Commission data showed on Friday.
The value of the dollar's net short position fell to $1.98 billion in that week, down sharply from $11.77 billion the previous week. That was the smallest since early February and well off a net short position worth $20.7 billion in mid-September.
The euro was steady at $1.4341, little changed from late New York trade on Friday when it fell as low as $1.4262 on trading platform EBS, its lowest since Sept. 4.
The euro was on defensive after ECB Vice President Lucas Papademos said on Friday the ECB would not change plans to tighten its collateral rules at the end of next year should Greek sovereign debt fall below the required "A-" standard, analysts said.
The euro fell below 1.4900 Swiss francs in early Asian trade and hit nine-month lows before recovering to trade at 1.4925 francs, down 0.2 percent on the day.
It was down 0.1 percent against the yen at 129.67 yen.
The dollar fell 0.1 percent to 90.31 yen, capped by expectations for more selling orders from Japanese exporting companies trying to repatriate overseas earnings after the dollar gained to a six-week high of 90.91 yen on Friday.
Data showed Japan's exports fell 6.2 percent in November from a year earlier, slightly less than economists' median forecast, thanks to expanding demand from the rest of Asia. (Editing by Chris Gallagher)