Fears that a Greek exit from the euro zone will worsen the debt crisis facing other European nations gripped financial markets on Wednesday, sending shares and other riskier assets lower as investors shifted funds into safe havens like the U.S. dollar.

The euro dipped below $1.27 to a four-month low, the main index of top European shares, the FTSE Eurofirst 300 <.FTEU3>, touched its lowest level for 2012, while U.S. stock futures pointed to a weak day on Wall Street.

The probability that Greece will leave the single currency rose markedly after political leaders in Athens failed on Tuesday to form a government, forcing another round of elections. Opinion polls show this is likely to be won by leftist parties opposed to the country's bailout deal.

In response, markets have moved to price in a Greek exit from the 17-member bloc, but are uncertain about the impact this will have on the rest of the region, while big investors have largely retreated to the sidelines, adding to the volatility.

"The idea that you can contain the spillover, the contagion, into the likes of Portugal, the likes of Spain, I just don't see that as being feasible," said James Ashley, senior European economist at RBC Capital Markets.

Peripheral euro zone sovereign bonds have taken the brunt of the selling pressure as some investors withdraw to safe havens like German government debt. Price moves were most pronounced in the market for insuring bonds against a potential default.

The Italian five-year Credit Default Swap (CDS) was 16 basis point (bpts) higher at 510 bpts in European morning trade, while the Spanish 5-year CDS widened 4.5 bpts to hit an all time peak of 546 bpts.

In the cash market moves were less dramatic, with 10-year Spanish bond yields easing to 6.35 percent after making big gains on Tuesday. The Italian equivalent debt was little changed at 6.01 percent.

The yield spread of all major emerging sovereign bonds over safer U.S. Treasuries however widened to be near 3-1/2-month highs of 386 basis points.

"The re-weighted probability of Greece leaving EMU has led to a sharp widening of government bond spreads, suggesting that long-term capital is leaving the periphery of Europe," Morgan Stanley said in a note to clients.

There were also signs in Athens that the prospect of a rapid devaluation of any new currency if the country leaves the euro was concerning ordinary Greeks.

Central bank head George Provopoulos told political leaders savers had withdrawn at least 700 million euros ($894 million) from the nation's banks on Monday.

The euro dropped to $1.2681 against the dollar putting it on track to test the January low of $1.2624, below which would mark the euro's lowest level since August 2010.

"The bias is still for a lower euro and a $1.26 target for mid-year looks pretty appropriate" said Jeremy Stretch, head of currency strategy at CIBC.

The dollar rose to its highest in four months against a basket of currencies <.DXY>, while the euro also hit a three-month low versus the yen.

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Reuters Insider on markets: http://link.reuters.com/zud38s

Euro zone debt crisis: http://r.reuters.com/hyb65p

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GROWTH IMPACT

The potential for a "disorderly" outcome, either directly from Greece leaving the euro or as related contagion worsens the already stagnant euro zone economy, has sent tremors through world equity and commodity markets.

Emerging market stocks as measured by the MSCIEF index <.MSCIEF> plunged 2.58 percent, with the index close to erasing all its year-to-date gains on its way to posting its biggest one-day loss in six months.

Weakness in Asian share markets sparked by the Greek crisis have already pushed MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> down 3.3 percent to a four-month low.

MSCI's global equity index <.MIWD00000PUS> was down 0.9 percent to 304.95 and is now up less than 2 percent for the year to date.

European shares were hit by a broad-based sell-off, with the FTSEurofirst 300 index <.FTEU3> down 0.7 percent to 990.54 points, having also dropped 0.7 percent on Tuesday.

Spain's IBEX 35 <.IBEX> fell 0.5 percent while Italy's FTSE MIB <.FTMIB> weakened by 1.7 percent.

Oil prices slid along with world shares and industrial commodities like copper in the general move away from riskier assets, but its fall was accentuated by a surprise build in U.S. crude inventories.

Brent crude was down $1.21 at $111.03 a barrel and U.S. oil was down $1.52 to $92.46 a barrel.

Brent crude oil fell to $110.82 cents a barrel and gold extended its losses to be down $13.34 at $1,530.76 an ounce, its weakest level since late December.

Gold gained nothing from flows into safe havens and fell for a fourth straight day to its lowest since late December as investors sold the precious metal to profit from the strength in the U.S. dollar.

Spot gold was down 0.6 percent at $1,534.54 an ounce, having dropped by nearly 3.8 percent in the last four days - its longest stretch of consecutive losses in nearly five months.