By Anora Mahmudova and Barbara Kollmeyer, MarketWatch

Valeant jumps on deal news; oil, euro tumble

NEW YORK (MarketWatch) -- U.S. stocks struggled to push higher on Monday as a drop in oil prices once again hit energy companies.

A pickup in merger-and-acquisition activity in the pharmaceutical industry helped push health-care stocks slightly higher.

The S&P 500 (SPX) was weighed down by losses in seven of the main 10 sectors. Energy, financials and telecoms led the losses.

The Dow Jones Industrial Average (DJI) retreated from the record closed notched on Friday. About two-thirds of its 30 members were trading lower. Boeing Co. (BA) was the biggest decliner, while UnitedHealth Group Inc. led gainers.

The Nasdaq Composite (RIXF) switched between small gains and losses. Biotechs led gains, lifted by a deal news. Friday's loss would break an eight-session winning streak for the tech-heavy index.

(http://www.marketwatch.com/story/knocking-down-nasdaq-5000-as-us-dollar-sentiment-hits-extremes-2015-02-23)10 stocks that are pushing the Nasdaq to 5,000 (http://www.marketwatch.com/story/10-stocks-that-are-pushing-the-nasdaq-to-5000-2015-02-23)

David O'Malley, chief executive officer at Penn Mutual Asset Management, said geopolitical news has tended to dictate market direction at the open, with money flows then pushing stocks higher in afternoon trading.

"There is a 180-degree shift in sentiment in all markets. In January, investors were worried the U.S. will have deflationary problems, but the Fed eased fears with [reassurances] to be patient and data-dependent while money is pouring into equity funds," O'Malley said.

Steven Wieting, global chief investment strategist at Citi Private Bank, said investors are waiting to see the positive economic effects of falling oil prices.

"We have seen immediate effects of lower oil prices in reduced earnings and cuts in capital expenditures by energy companies, but consumers are not spending their windfall just yet," Wieting said.

Read: Three things Yellen could say to surprise investors (http://www.marketwatch.com/story/three-things-yellen-could-say-to-surprise-investors-2015-02-20)

Economic preview: U.S. economy's growth not touching all the bases (http://www.marketwatch.com/story/us-economys-growth-not-touching-all-the-bases-2015-02-22)

(http://www.marketwatch.com/story/us-economys-growth-not-touching-all-the-bases-2015-02-22) (http://www.marketwatch.com/story/us-economys-growth-not-touching-all-the-bases-2015-02-22) (http://www.marketwatch.com/story/us-economys-growth-not-touching-all-the-bases-2015-02-22) (http://www.marketwatch.com/story/us-economys-growth-not-touching-all-the-bases-2015-02-22)Monday deals: Valeant(VRX) shares surged after it said Sunday that it will buy Salix (http://www.marketwatch.com/story/valeant-pharmaceuticals-to-buy-salix-for-about-10-billion-2015-02-22-161035324)(SLXP) for about $10 billion in cash, which will take it into a multibillion-dollar market for drugs that treat stomach disorders.

Bristol-Myers Squibb(BMY) announced on Monday an agreement to buy privately-held biotechnology company Flexus Biosciences in a deal that could be valued at up to $1.25 billion.

3M Co.(MMM) said Monday that it has entered into a definitive agreement to buy Polypore International Inc.'s (PPO) separations media business for a total purchase price of $1 billion (http://www.marketwatch.com/story/3m-to-buy-polypore-unit-for-1-billion-2015-02-23). Polypore shares jumped 12%, while 3M was flat.

Shares in Discovery Communications (DISCA) jumped, making it the best performer on the S&P 500. Shares rose after news reports on Sunday that 21st Century Fox was in talks to purchase the cable operator. A Fox spokesperson denied the rumors, saying 'there is no truth" in the report. 21st Century Fox was part of MarketWatch parent News Corp. until being spun off in 2013.

Apple Inc.(AAPL) said Monday that it will invest EUR1.7 billion ($1.92 billion) (http://www.marketwatch.com/story/apple-to-invest-19-billion-in-european-data-centers-2015-02-23-5912328) to build two data centers in Europe that will run 100% on renewable energy -- in County Galway, Ireland and central Jutland, Denmark. Shares were 1.6% higher.

For more notable movers, read our Movers & Shakers column (http://www.marketwatch.com/story/dish-dillards-express-scripts-earnings-in-focus-2015-02-23).

(http://www.marketwatch.com/story/dish-dillards-express-scripts-earnings-in-focus-2015-02-23) (http://www.marketwatch.com/story/dish-dillards-express-scripts-earnings-in-focus-2015-02-23)Other markets:European stocks (http://www.marketwatch.com/story/european-stocks-higher-as-greek-bailout-extended-2015-02-23) got a lift from Greece's bailout extension, while the euro (EURUSD) fell 0.7% against the dollar after German business confidence improved for a fourth straight month in February, but less than expected.

In Asia, the Nikkei 225 index (http://www.marketwatch.com/story/japan-stocks-advance-for-fourth-day-to-15-year-high-2015-02-23) advanced for a fourth session to another 15-year high.

Oil prices (CLJ5) reversed (http://www.marketwatch.com/story/oil-rises-marginally-gains-capped-by-high-us-supplies-2015-02-23-2103192) an earlier gain, falling $1.36 to settle at $49.45 a barrel, while gold (GCJ5) dropped $4.10 (http://www.marketwatch.com/storyno-meta-for-guid) to finish at $1,200.80 an ounce.

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