* Global stocks plunge as U.S. auto rescue prospect dims
* Oil falls under $50 a barrel to a three-year low
* Debt rallies after U.S. jobless data raises growth fears
* U.S. dollar, euro extend losses vs yen on risk aversion (Adds close of European markets, freshens U.S. pricings)
By Herbert Lash
NEW YORK, Nov 20 (Reuters) - Fears of a deep global recession ripped through global markets on Thursday, sending U.S. stocks to six-year troughs, yields on government debt to record lows and the price of oil below $50 a barrel.
Hopes of a deal that would rescue ailing U.S. automakers helped U.S. stocks claw back to break-even levels.
The bleak economic outlook triggered technical breaches by major stock indexes around the world, an event that could unleash even greater turmoil as sentiment darkens among investors and threatens to send markets spiralling into a deeper slump.
Crude oil <CLc1> slipped nearly 9 percent to a low of $48.85 a barrel at one point.
The stampede into low-risk assets from stocks pushed ultra-short U.S. government bill rates toward zero percent and two-year yields to a series of record lows.
The S&P 500, the benchmark for U.S. institutional investors, fell to its lowest level since October 2002, while other U.S. indexes and benchmarks in Europe and Asia set fresh 5-1/2-year lows. Two out of every five of the 3,229 issues traded on the New York Stock Exchange hit 52-week lows.
The stock of corporate icons Citigroup, General Motors and Ford plunged anew as all three traded below $5 a share before news of a possible legislation to help the automakers led GM and Ford, which almost fell below $1, to sharply rebound.
Debt yields also fell to record lows. The 30-year U.S. Treasury bond declined to lows last seen in the early 1960s, and U.S. credit default swaps widened to levels that suggest investors expect the worst wave of investment-grade corporate bond defaults since at least 1980.
Fresh economic data reinforced the market gloom. The Conference Board's index of Leading Economic Indicators fell to its lowest level in four years in October, factory activity in the U.S. Mid-Atlantic region fell to an 18-year low in November, and the number of American workers lining up for first-time jobless benefits surged to a 16-year high last week.
"Anxiety about the financial markets is shifting to anxiety about fundamentals and the real economy, and that's keeping the overall levels of risk aversion very high," said Vassili Serebriakov, currency strategist at Wells Fargo in New York.
"We've had disappointing U.S. economic data and we believe the bear market in equities will continue, lending more support to the dollar and yen."
U.S. indexes pared losses before midday after an early morning plunge, and the Nasdaq and Dow inched into positive terrority.
Declining prices in one asset class fed declines in another, analysts said but the biggest indicator in market sentiment in recent weeks has been stocks.
Shortly after 2 p.m., the Dow Jones industrial average <
> was down 29.71 points, or 0.37 percent, at 7,967.57. The Standard & Poor's 500 Index <.SPX> was down 7.76 points, or 0.96 percent, at 798.82. The Nasdaq Composite Index < > was up 2.54 points, or 0.18 percent, at 1,388.96.The picture in Europe was no better. Commodities, a harbinger of global economic growth, were among the biggest losers on the index of leading European companies.
The FTSEurofirst 300 <
> index of top European shares closed down 3.8 percent at 781.06 points. The index has shed about 48 percent so far this year.Among mining companies, Vedanta Resources <VED.L> plunged almost 13 percent, Xstrata <XTA.L> shed more than 11 percent, while Kazakhmys <KAZ.L> and Rio Tinto <RIO.L> each fell about 10 percent.
Oil stocks also weakened as crude prices <CLc1> fell more than 8 percent.
Total <TOTF.PA> and BP <BP.L> were down between 4.4 percent and 4.9 percent.
With economies weakening worldwide, Deutsche Bank said crude oil could fall to as low as $40 a barrel next year.
"Weakness in stocks reflects weakness in the economy at the moment looking forward, but I think the general trend in oil is lower anyway," said Sucden's head of research Michael Davies.
"It's a bit of a chicken or egg thing. Everything's moving together, it's hard to say what's leading."
U.S. light sweet crude oil <CLc1> fell $4.92 to $48.70 a barrel.
The U.S. dollar and euro extended losses against the yen, each falling more than 1 percent, as global recession fears pushed risk-averse investors into the Japanese currency.
Risk aversion benefits the yen as investors pull money out of higher-yielding assets such as stocks and commodities, positions that were financed with a cheaply borrowed yen.
The dollar, however, gained against high-yield currencies, and rose against a basket of major currencies; the U.S. Dollar Index <.DXY> was up 0.14 percent at 87.921. Against the yen, the dollar <JPY=> was down 0.39 percent at 95.53.
The euro <EUR=> rose a bare 0.05 percent to $1.2528.
Short-dated yields on euro zone government bonds hit their lowest levels in over five years. Two-year bond yields <EU2YT=RR> were 11.5 basis points lower at 2.056 percent, having fallen as low as 1.989 percent.
The benchmark 10-year U.S. Treasury note <US10YT=RR> rose 42/32 in price to yield at 3.19 percent. The 2-year U.S. Treasury note <US2YT=RR> added 5/32 in price to yield 0.9909 percent.
Spot gold prices <XAU=> rose $16.10 to $748.50 an ounce.
Overnight in Asia, Japan's Nikkei average <
> dropped nearly 7 percent.The MSCI All-Country World Index <.MIWD00000PUS> was down 3.2 percent at 196.12 -- its lowest level since May 2003. (Reporting by Ellis Mnyandu, Richard Leong, Steven S. Johnson in New York and Rebekah Curtis, Kirsten Donovan, Chris Baldwin and Pratima Desai in London, writing by Herbert Lash; Editing by Theodore d'Afflisio)