* Upbeat U.S. economic data seen supportive of oil
* Euro recovery cut short by Fitch downgrade of Portugal
* Oil prices near two-year high, gold falls
* Global equity prices mixed in thin pre-holiday trade (Updates with US market open, changes dateline, byline)
By Daniel Bases
NEW YORK, Dec 23 (Reuters) - Crude oil prices rose to two year highs on Thursday helped by further evidence of a strengthening American economy, but world stock prices were little changed near two year highs also.
The euro came under a little pressure after Fitch Ratings downgraded Portugal's debt one notch to A-plus from AA-minus citing a difficult financing environment and recession for the economy in 2011.
Most financial markets were left to meander in thin trade ahead of the Christmas and New Year holidays, though stocks remained around their best levels since before the collapse of investment bank Lehman Brothers in September 2008.
U.S. economic data showed signs of further improvement with new claims for jobless benefits falling, and consumer spending increasing in November for a fifth straight month. Orders for long-lasting manufactured goods excluding transportation increased 2.4 percent, the largest increase since March, after a 1.9 percent drop in October. [
]The U.S. data contrasted with developments in Europe where China said it was willing to help countries in the euro zone return to economic health and would support the International Monetary Fund bailout package for the bloc. [
]In mid-morning trade, the Dow Jones industrial average <
> rose 8.63 points, or 0.07 percent, to 11,568.12. However, the Standard & Poor's 500 Index <.SPX> fell 2.05 points, or 0.16 percent, to 1,256.79. The Nasdaq Composite Index < > lost 6.33 points, or 0.24 percent, to 2,665.15.Retail stocks got a boost as Bed Bath & Beyond Inc <BBBY.O>rose 6.16 percent to $50.60 after it beat quarterly profit estimates and forecast a strong holiday season. [
]On Wednesday, the S&P 500 rose to its highest level since the collapse of Lehman Brothers, led by bank stocks.
"We are continuing to make new highs as volume tails off, and the question is will it lead to some potential weakness into early next year," said Ryan Detrick, senior technical strategist at Schaeffer's Investment Research.
"Some optimism is creeping in, but bigger picture we think there could be a correction of 5 to 7 percent," towards the second half of January, he said.
In Europe, shares gave up early gains. The FTSEurofirst 300 <
> index of top European shares was down 0.1 percent at 1,146.69 points, having reached as high as 1,149.05 earlier.Mining companies BHP Billiton <BLT.L>, Rio Tinto <RIO.L> and Xstrata <XTA.L> fell between 0.7 and 1 percent.
CURRENCY AND DEBT
Fitch's downgrade cut the rebound rally for the euro against the greenback short. The currency fell 0.03 percent at $1.3095 <EUR=EBS> in the wake of Fitch's decision.
In its statement, Fitch said it retains a negative outlook for Portugal's rating and that while the budget target for 2011 remains "extremely" challenging with a recession expected next year, a sustainable recovery is seen from 2012. In addition, the firm does not assume Portugal will seek a bailout program from the European Union or International Monetary fund. [
]Against the yen, the dollar fell 0.74 percent to 82.93 <JPY=>. Japanese markets were closed on Thursday in observance of the Emperor's birthday.
Against a basket of currencies made up of its major trading partners, the dollar fell 0.31 percent <.DXY>
Benchmark 10-year U.S. treasuries fell 7/32 of a point in price, pushing the yield up to 3.83 percent <US10YT=RR>.
Crude oil prices for February delivery on the New York Mercantile Exchange rose 1.0 percent to $91.48 a barrel on Thursday. Cold weather in the United States plus shrinking U.S. stockpiles and projections among OPEC members and analysts that prices could reach $100 a barrel soon, supported the market even with the greenback's strength.
Spot gold prices <XAU=> fell $4.75, or 0.34 percent, to $1379.80. (Additional reporting by Rodrigo Campos, Wanfeng Zhou, Steven C. Johnson, Natsuko Waki, Atul Prakash)