U.S. stocks rose on Monday, lifted by merger news and solid earnings that suggested Wall Street may have the strength to rally further.

The S&P 500 moved above a key short-term resistance level to its highest since June 2008 after the index ended the week with its best gain in nine weeks.

It's the absence of headline risks that is pushing the market higher. We clearly know that the Egyptian turmoil doesn't necessarily mean oil scarcity ... so momentum is moving the market higher, said Joe Battipaglia, market strategist at a private client group for Stifel Nicolaus in Philadelphia.

Dow Jones industrial average <.DJI> was up 82.88 points, or 0.69 percent, at 12,175.03. The Standard & Poor's 500 Index <.SPX> was up 10.15 points, or 0.77 percent, at 1,321.02. The Nasdaq Composite Index <.IXIC> was up 20.40 points, or 0.74 percent, at 2,789.70.

Diversified industrial company Danaher Corp agreed to buy medical diagnostics company Beckman Coulter Inc for about $6.8 billion and oil drilling company EnsCo Plc will buy rival Pride International Inc

for about $7.3 billion.

The deals provided the latest indication stock valuations are considered attractive. Danaher Corp rose 3.8 percent to $49.79 and Beckman Coulter rose 9.8 percent to $82.53.

EnsCo fell 2.8 percent to $52.95 while Pride International rose 16.9 percent to $40.19.

Loews Corp reported its best quarter of the year, posting a better-than-expected 16 percent jump in profit. The stock gained 5.7 percent to $43.78.

More than 70 percent of S&P 500 companies that have reported results so far posted better-than-expected earnings, according to Thomson Reuters data. Investors expect aggregate earnings rose 37 percent in the last quarter, the highest estimate for that period in more than 10 months.

Adding to Wall Street's image problem, Nasdaq OMX Group said on Saturday that computer hackers had infiltrated the operator of the Nasdaq Stock Exchange.

Hacking is going to be a global problem and like a war breaking out, it is hard to hedge against it. There will be concerns, but it's not going to have an impact on how investors see opportunities for the stock market, Battipaglia said.

Basic materials stocks rose as the price of copper hit a record on concerns about supply and as economic data recently boosted the outlook for demand. Freeport McMoRan Copper & Gold Inc shares rose 1.1 percent to $57.42 and the S&P materials sector <.GSPM> led gains with a 1 percent rise.

Struggling U.S. Internet company AOL Inc has agreed to buy The Huffington Post, the rapidly growing news, analysis and lifestyle website, for $315 million. AOL shares fell 1.3 percent to $21.59.

UBS raised its 2011 target for the S&P 500 index by 7.5 percent to 1,425 from 1,325, citing an improving outlook for the economy and earnings.

(Reporting by Angela Moon, Editing by Kenneth Barry)