* S&P revises its credit outlook on U.S. to negative
* Potential Greek debt restructuring in focus
* Finnish vote adds concerns about euro zone bailouts (Updates prices, adds details, comment)
NEW YORK, April 18 (Reuters) - Worries over Europe's debt crisis spurred a sell-off in global stocks and the euro currency on Monday, with a downgrade of the U.S. credit outlook further battering investor confidence.
Growing unease about the possibility of Greece restructuring its debt and the rise of an anti-euro party in Finland exacerbated anxiety over how European policy-makers will handle the region's festering debt and bank problems.
Rating agency Standard & Poor's revised its outlook on the United States to negative from stable, citing a "material risk" that policymakers may not reach agreement on a plan to trim its large budget deficit. See [ID:nN18195555]
While the agency maintained the country's top AAA credit rating, it said the move signals there's at least a one-in-three chance that it could cut its long-term rating on the United States within two years.
"On a day when sovereign debt troubles have returned to haunt the euro, S&P's announcement added salt to the wound," said Kathy Lien, director of research at GFT in New York. "Investors were risk averse going into the NY open and will now remain cautious or nervous throughout the North American trading session."
MSCI's all-country world stock index <.MIWD00000PUS> started what is in many places a holiday-shortened week by losing 1.7 percent.
Wall Street stocks fell sharply. The Dow Jones industrial average <.DJI> dropped 196.02 points, or 1.59 percent, to 12,144.34. The Standard & Poor's 500 Index <.SPX> dropped 19.18 points, or 1.45 percent, to 1,300.11. The Nasdaq Composite Index <.IXIC> dropped 5.18 points, or 1.82 percent, to 2,714.28.
In Europe the FTSEurofirst 300 <.FTEU3> was off 1.8 percent. The fall wiped out the European index's gains this year, leaving it in negative territory for 2011.
In a weekend election, Finnish voters handed the anti-euro True Finns party a crucial role in parliament and possibly a path into government.
Finland's parliament has the right to vote on European Union requests for bailout funds, meaning it could in theory hold up costly plans to shore up Portugal and bring stability to debt markets. [ID:nLDE73G02L] [ID:nHEL010101]
Talk about Greek debt restructuring has also boiled up in recent weeks, including a Greek newspaper report on Monday that the government had asked the International Monetary Fund and European Union to start discussions on a restructuring.
A Greek finance ministry source said the report was not true. [ID:nATH006025] [ID:nLDE73H0DR]
Disappointing earnings and concerns about Japan's coming reporting season further eroded appetite for stocks and other risky assets.
Gold and silver hit new record highs.
The euro hit a 2-week low against the dollar on concerns
about Greek restructuring and the Portuguese bailout. It fell
1.2 percent to $1.4357
The dollar lost 0.7 percent to 82.54 yen, after hitting a session low of 82.48 yen, the weakest in more than two weeks.
In the bond market, the yield on the 30-year Treasury bond