* Global stocks turn lower on fears over U.S. bank plans
* Bonds erase majority of losses as stocks turn lower
* Oil falls below $40 a barrel as equity markets fall
* Dollar strengthens in safe have bid, yen declines (Recasts with U.S. markets, changes dateline; previous LONDON)
By Herbert Lash
NEW YORK, Feb 23 (Reuters) - Global stocks turned sharply lower on Monday, with the Dow falling to lows last seen in 1997, on growing doubts about U.S. government's plans to shore up beleaguered banks, driving up the bid for assets viewed as relatively safe.
The Dow plunged in midday trade, as markets reversed course after an initial warm reception to rising expectations that the U.S. government will increase its stake in Citigroup <C.N>, instead of fully nationalizing it.
World stocks had climbed and government bonds traded lower before U.S. markets opened.
U.S. banking regulators pledged to provide more capital to banks as needed and keep large institutions viable through a program to "stress test" banks, to be launched on Wednesday, called the Capital Assistance Program. [
]But the initial euphoria soon waned as after reflection, some saw an increased government stake in Citigroup as a step toward nationalization.
"The market initially saw it as 'glass half full' but the other way of looking at it is Citi taking one huge step toward public ownership," said Richard McGuire, head of rates strategy at RBC Capital Markets in London. That "is really the doomsday scenario for anyone holding Citigroup shares," he said.
U.S. stocks fell more than 2 percent, and the benchmark S&P 500 broke through a bear market closing low of 752.44 set on Nov. 20. The index still traded higher than intraday lows set then. The Dow slid to lows last seen in 1997.
While Citigroup was up more than 8 percent, after paring double-digit gains, advancing volume on the New York Stock Exchange outpaced declining volume by more than 4 to 1.
"There's just uncertainty about what stance the government will take, whether there's nationalization or not, or some form of it that we're in currently," said Peter Boockvar, equity strategist at Miller Tabak & Co.
"But it doesn't matter, the economy remains weak, the market is worried about earnings," Boockvar said.
After 1 p.m., the Dow Jones industrial average <
> was down 155.71 points, or 2.11 percent, at 7,209.96. The Standard & Poor's 500 Index <.SPX> was down 18.44 points, or 2.39 percent, at 751.61. The Nasdaq Composite Index < > was down 37.28 points, or 2.59 percent, at 1,403.95.European shares closed at nearly six-year lows as regional banks fell. The FTSEurofirst 300 <
> index of top European shares closed off 0.9 percent at 729.39 points, and is now down 12 percent this year after plunging 45 percent in 2008.Several banks fell sharply, with UBS <UBSN.VX> down 9 percent and Deutsche Bank <DBKGn.DE> off more than 5 percent.
"It's very difficult to make an investment case for banks because of the uncertainty over how much capital dilution they will suffer in order to be kept in business," said Andrew Bell, head of research at Rensburg Sheppards.
In euro zone government debt markets, bunds recovered earlier losses to close only slightly down as fears over the U.S. banking sector hit European equities,
U.S. Treasuries turned higher, even as investors awaited the sale of $94 billion of new supply this week, which had depressed prices earlier in the session.
The benchmark 10-year U.S. Treasury note <US10YT=RR> was up 1/32 in price to yield 2.79 percent. The 2-year U.S. Treasury note <US2YT=RR> was unchanged in price, yielding 0.97 percent.
The euro surrendered gains against the dollar after European Central Bank president Jean-Claude Trichet said the euro-zone financial system is under severe strain.
The dollar rose against a basket of major trading-partner currencies, with the U.S. Dollar Index <.DXY> up 0.58 percent at 87.092.
The euro <EUR=> fell 0.79 percent to $1.2739. Against the yen, the dollar <JPY=> was up 1.64 percent at 94.66.
Oil slipped below $40 a barrel as the U.S. stock market retreated despite a report that the U.S. government was in talks on increasing its stake in Citigroup. [
]U.S. light sweet crude oil <CLc1> fell 99 cents, or 2.47 percent, to $39.04 a barrel.
But investors worry that losses from credit cards, emerging markets, trading and toxic assets at Citigroup could overwhelm Chief Executive Vikram Pandit's efforts to restore its fiscal footing. Analysts do not expect Citigroup to be profitable in 2009 or 2010. (Reporting by Ellis Mnyandu, Ellen Freilich and Nick Olivari in New York; and Christopher Johnson, Barbara Lewis and Atul Prakash in London; writing by Herbert Lash, Editing by Chizu Nomiyama)