U.S. blue chips declined a bit Monday as concern about weaker-than-expected sales at Wal-Mart Stores Inc. (WMT) offset sharply lower oil prices.

The Dow Jones industrial average slipped 3.76 points, or 0.03 percent, to end at 12,086.50. The Standard & Poor's 500 Index was up just 0.59 of a point, or 0.04 percent, to finish at 1,377.93. The Nasdaq Composite Index gained 13.15 points, or 0.56 percent, to close at 2,363.77.

But the Nasdaq finished the session higher, buoyed by gains in Yahoo Inc. (YHOO) after Merrill Lynch (MER) upgraded the stock to "buy," as well as by a jump in shares of American Power Conversion (APCC) on acquisition news.

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Wal-Mart shares fell 2.4 percent, or $1.20, to $49.53 on the New York Stock Exchange and were the biggest drag on the blue-chip Dow average. The world's largest retailer blamed the lower sales growth on disappointing apparel demand and disruption from store remodeling projects. .

"A drop in oil prices is always welcome, but the Wal-Mart report was bad enough to dampen some of the enthusiasm," said Michael Metz, chief investment strategist at Oppenheimer & Co. in New York.

Diminished concern over a threat to Saudi Arabia's oil and economic installations helped crude oil prices fall, with December crude dropping $2.39 to settle at $58.36 a barrel on the New York Mercantile Exchange.

Shares of jet maker Boeing Co. (BA) rose 0.6 percent, or 48 cents, to $80.22 on the NYSE. Brazil's Gol airline said it increased its order for Boeing aircraft to 87 from 67.

The stock, among the Dow's biggest gainers, helped curb its decline.

But U.S. phone company Verizon Communications (VZ), another Dow component, fell after news that its Internet subscriber growth disappointed some analysts.

Verizon fell 3.1 percent, or $1.19, to $37.65 on the NYSE. The stock was the second-heaviest weight on both the Dow and the S&P 500.

In Nasdaq trading, Yahoo gained 2.4 percent, or 61 cents, to $25.95 after Merrill Lynch upgraded the Internet media company's stock. .

American Power Conversion shares jumped 26.4 percent, or $6.26, to $30.10 and gave the biggest lift to the Nasdaq 100 after French electrical engineering company Schneider Electric said it had agreed to buy American Power.

Software makers, including Oracle Corp. (ORCL) and Intel Corp. (INTC), also rose, rebounding from heavy losses Friday. Oracle rose 2.3 percent, or 42 cents, to $18.52 and Intel gained 0.8 percent, or 16 cents, to $21.26 on the Nasdaq.

Volume was moderately active on the NYSE, where about 1.43 billion shares changed hands, below last year's daily average of 1.61 billion. On the Nasdaq, about 1.77 billion shares were traded, below last year's daily average of 1.80 billion.

Advancers outpaced decliners on the Big Board by a ratio of about 5 to 6, while on the Nasdaq, more than eight stocks rose for every seven that fell.

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