U.S. stocks advanced Monday, helped by deal news, cheaper oil and positive broker comments on the chip sector.

The Dow Jones industrial average was up 42.30 points, or 0.34 percent, to end at 12,318.62. The Standard & Poor's 500 Index was up 3.75 points, or 0.27 percent, to finish at 1,406.60. The Nasdaq Composite Index was up 14.74 points, or 0.62 percent, to close at 2,402.29.

Among acquisitions, private equity group Kohlberg Kravis Roberts & Co. said it would buy discount retailer Dollar General Corp. (DG) for about $6.9 billion.

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Crude oil prices settled below $59 a barrel, relieving some worries about energy costs.

The stock of Boeing Co. (BA) was the top positive influence on the Dow average, gaining 1.9 percent, or $1.69, to $91.20 on the New York Stock Exchange. Boeing chalked up more than $4.5 billion in commercial plane orders from several clients, including Continental Airlines (CAL) Inc. and carriers in Russia and Kuwait.

In tech news, brokerage and investment bank Lehman Brothers upgraded its rating on specialty chip maker Xilinx Inc., saying Wall Street estimates on the stock may be conservative. The Philadelphia Stock Exchange index of semiconductors gained 0.9 percent, while shares of chip maker Intel Corp. rose 2 percent.

"When you see all this M&A activity continue, especially on the private equity side, people think, 'If these guys can find bargains, and they still have so much money, why be so bearish?"' said David Straus, portfolio manager with Johnston Lemon Inc. in Washington.

Concerns about growing losses in the subprime mortgage market helped keep indexes near flat earlier in the day.

New Century Financial Corp. (NEW), the largest independent U.S. subprime mortgage lender, said its lenders plan to halt financing, pushing the company closer to bankruptcy.

Trading in shares of New Century was halted by the New York Stock Exchange. The Big Board is either moving to delist the lender or keep it under review, according to a source close to the matter.

Before the opening bell, New Century's stock was trading around $1.50. Less than a year ago, New Century shares traded as high as $51.

Right after the close, Standard & Poor's Ratings Services said it cut its rating on New Century to "D," noting that some violations of its financial arrangements "amount to events of default."

"People keep waiting for the sky to fall with all of the subprime issues. It's falling but in a very containable way, so it's not having a dramatic effect yet on all of the other parts of the market," said Jim Fehrenbach, head of Nasdaq trading at Piper Jaffray in Minneapolis.

Shares of chip maker Texas Instruments rose 0.4 percent, or 13 cents, to $32.59 ahead of its mid-quarter update, expected after the close.

In Nasdaq trading, Intel shares rose 2 percent, or 38 cents, to $19.48, while shares of Xilinx gained 2 percent, or 50 cents, to $26.15.

Also in M&A news, U.S. pharmaceutical company Schering-Plough said it will buy Organon BioSciences, a unit of Dutch drug maker Akzo Nobel , for $14.5 billion. Schering shares gained 0.4 percent, or 10 cents, to $23.95 on the NYSE.

The U.S.-listed shares of Akzo Nobel shot up 16.5 percent, or $10.02, to $70.83 on Nasdaq.

Dollar General shares surged 25.6 percent, or $4.29, to $21.07 and topped the NYSE's list of biggest percentage gainers.

Countrywide Financial Corp. , the largest U.S. mortgage lender, said it had minimal exposure in February to loans of less than prime quality but may still experience fluctuating earnings in the near term due to turmoil in the subprime market.

Brokerage Wachovia cut its rating on Countrywide, which fell 2.7 percent, or 96 cents, to $35.14 on the NYSE.

Volume was moderate on the NYSE, where about 1.47 billion shares changed hands, below last year's estimated daily average of 1.84 billion. On the Nasdaq, about 1.65 billion shares traded, below last year's daily average of 2.02 billion.

Advancers outnumbered decliners on the NYSE by a ratio of about 7 to 4, while on the Nasdaq, about three stocks rose for every two that fell.

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