* Euro falls 1 percent below $1.5; stocks stumble
* Dubai debt problems dent risk appetite, support dollar
* Traders cite SNB selling Swiss franc; SNB declines comment
* Dollar off 14-yr lows vs yen; no intervention seen
(Releads, adds S&P move, Lagarde comments, updates prices)
By Tamawa Desai and Jamie McGeever
LONDON, Nov 26 (Reuters) - The dollar gained sharply in holiday-thinned trade on Thursday as renewed risk aversion prompted investors to shed riskier assets.
A more than 3 percent fall in European stocks and a 2 percent drop in U.S. futures encouraged traders to trim positions that involved selling dollars for other currencies and assets like commodities.
The euro extended losses as ratings agency Standard & Poor's put the credit ratings of four Dubai banks on negative outlook and stocks fell further. The negative outlook for the banks is due to their exposure to Dubai World, which is seeking a debt standstill.
The single currency was also buoyed as France's Economy Minister Christine Lagarde also said that the level of the euro against other currencies was hurting European exporters.
By 1628 GMT, the euro hovered near the day's low of $1.4960 , down 1.1 percent on the day. It had risen more than 1 percent on Wednesday to a 15-month high of $1.5145 on EBS.
The euro also hit a near 2-month low against the yen at 129.52 yen.
Dubai's shock move on Wednesday to restructure its biggest corporate debtor, Dubai World, and delay repayment on some of the company's $59 billion of liabilities, dented risk appetite across asset markets on Thursday, to the dollar's benefit.
"While much of the moves are going to occur in rates and credit markets, it is also being reflected in stock markets and foreign exchange," said Lauren Rosborough, senior strategist at Westpac in London.
The dollar index, a barometer of its performance against six major currencies, rose 0.9 percent on the day at 74.965, up from a 15-month low of 74.170 earlier in the day.
But dollar-bearish sentiment remained intact on views U.S. interest rates would stay low for some time and on pressure for the dollar to weaken to correct the U.S.' imbalances.
SNB ACTS, JAPAN CHATS
The dollar also fell to its lowest level against the Swiss franc since April 2008, but the Swiss currency's rise was abruptly halted as the Swiss central bank was seen selling its currency, traders said.
The dollar rose back above 1.0000 francs, having earlier tumbled to just above 0.9900 francs on EBS.
Some market participants said the SNB bought up to $1 billion in early Europe hours. The SNB did not comment. More dollar/Swiss franc selling was seen later in the day.
"As well as the retest of the perceived intervention level of 1.50 franc in euro/Swiss franc, we would note Swiss franc's overnight rally took the trade-weighted index back through the level at which the SNB first intervened in March," said Adam Cole, global head of FX strategy at RBC Capital Markets.
"That is perhaps another reason to think the central back will act aggressively to prevent further strength."
In contrast, Japanese authorities refrained from acting on the yen's rise, saying they were watching the market cautiously. Japanese Finance Minister Hirohisa Fujii said Tokyo would respond to "abnormal" moves as needed.
The dollar was at 86.61 yen, after hitting a 14-year low. It had shot through a previous low of 87.10 yen to fall to 86.29 yen on trading platform EBS, its weakest level since 1995. Traders said 85 yen was now in the market's sights.
But analysts said the yen's appreciation was more a result of a falling dollar and Japan would need cooperation from the United States and Europe if it wanted to buy dollars.
"Unless the United States takes the stance that a one-sided fall in the dollar is unfavourable, the dollar's fall will likely continue," said Mitsuru Sahara, chief manager of currency derivatives trading at Bank of Tokyo-Mitsubishi UFJ.
"The possibility of Japan intervening depends on the pace of the dollar's fall versus the yen and its impact on other markets such as Japanese stocks and bonds."
For a snap analysis on yen intervention, see.
Japan has not intervened in currency markets since March 2004.
(Editing by Ron Askew and Andy Bruce) ((Reuters Messaging: jamie.mcgeever.reuters.com@reuters.net; +44 207 542 8510))