GLOBAL MARKETS-Euro gains as debt fears wane, S&P 500 tumbles

* Global stocks reverse course to fall on sour U.S. data

* Euro hits 8-week high vs dollar as sovereign fears wane

* U.S. crude slips on economic doubts, Brent bucks trend

* Bonds rise on equity weakness but remain stuck in range (Updates with close of U.S. markets)

By Herbert Lash

NEW YORK, Jan 19 (Reuters) - The euro rose to an eight-week high on Wednesday on increasing optimism that Europe can defuse its debt crisis, but equities fell on poor U.S. housing data and bank earnings, while a rally in commodities faded.

Traders said Asian sovereigns were again big buyers of the euro, forcing enough short-covering to help it outperform the U.S. dollar for the seventh session in the last eight. For details see [ID:nN19248643]

The euro climbed more than 1 percent to hit a session high of $1.3538 after slumping last week to a four-month low of less than $1.30 on worries that a debt crisis that had engulfed Greece and Ireland in 2010 would spread.

But solid bond auctions in Spain and Portugal have boosted spirits and talk that German officials were drafting contingency plans in case Greece defaults suggested they were working to prevent a deeper crisis. [ID:nLDE70I158]

"There is a growing sense of optimism that European leaders are finally getting their act together and working in a unified manner," said Samarjit Shankar, managing director of global foreign exchange strategy at BNY Mellon in Boston.

MSCI's all-country world index for stocks <.MIWD00000PUS> fell 0.5 percent, paring gains that had lifted the index earlier in the session to highs last seen in August 2008.

Stocks in Tokyo were poised to open lower, with the March futures contract that trades in Chicago for the Nikkei 225 <0#NK:> down slightly by 10 points at 10,475.

The Standard & Poor's 500 Index suffered its biggest decline in nearly two months after disappointing results at Goldman Sachs Group Inc <GS.N> and Wells Fargo & Co <WFC.N>. [ID:nN19236616]

Financials and technology stocks have fueled a surge that has pushed the benchmark index up nearly 10 percent since the start of December, leading some investors to say stocks are primed for a pullback.

"Even stocks here that are beating expectations are not acting favorably, so (for) the market it may be time for a pause, and that may be what we are seeing here," said Paul Mendelsohn, chief investment strategist at Windham Financial Services in Charlotte, Vermont.

Groundbreaking for new U.S. homes fell more than expected in December to the lowest in over a year, the Commerce Department said. [ID:nN19195756]

The Dow Jones industrial average <.DJI> closed down 12.64 points, or 0.11 percent, at 11,825.29. The Standard & Poor's 500 Index <.SPX> fell 13.10 points, or 1.01 percent, at 1,281.92. The Nasdaq Composite Index <.IXIC> slid 40.49 points, or 1.46 percent, at 2,725.36.

The Dow's decline was limited by International Business Machines Corp <IBM.N>, which climbed 3.4 percent following the release of strong earnings after the close on Tuesday. [ID:nN18146899]

Brent oil futures rose above $98 a barrel on supply concerns in the North Sea, but worries in the equity market about the economic recovery kept prices off the key $100 level and saw U.S. crude ease for a second day. [ID:nL3E7CJ09E]

ICE Brent crude for delivery in March <LCOc1> rose 36 cents to settle at $98.16 a barrel.

U.S. crude oil futures for February delivery <CLc1> fell 52 cents to settle at $90.86 a barrel, one day ahead of the contract's expiry, in relatively thin trade.

Copper retreated from a fresh record high in London, as profit-taking pressures mounted in response to weak U.S. equities and another large build in London inventories.

Gold rose for a third straight day on a weaker dollar and strong Asian physical demand, while an improving global economic outlook took platinum and palladium to multiyear highs. [ID:nLDE70I0UY]

U.S. gold futures <GCG1> rose $2 to settle at $1,370.20.

The dollar was down against a basket of major currencies, with the U.S. Dollar Index <.DXY> off 0.48 percent at 78.586.

U.S. Treasuries rose as corporate deal pricings fueled buying, while President Barack Obama and Chinese President Hu Jintao avoided a public clash on currency differences that might have rattled the bond market. [ID:nN19215065]

The benchmark 10-year U.S. Treasury note <US10YT=RR> was up 8/32, with the yield at 3.337 percent. (Reporting by Chuck Mikolajczak, Steven C. Johnson, David Sheppard, Emily Flitter and Frank Tang in New York; Writing by Herbert Lash; Editing by Kenneth Barry)