Wall Street opened little changed on Monday after posting six weeks of gains, but insurer Aetna's purchase of rival Coventry Health Care for $5.7 billion showed companies still see value in the market.
The European Central Bank sought to quash speculation about the shape of its planned bond-buying program, saying it was misleading to talk about decisions that had not yet been taken. That pressured the market somewhat as investors anticipate concrete action from the ECB.
Coventry shares jumped 19 percent to $41.46 after Aetna said it will pay a total value of $41.10 per share for the company, putting the deal at a 20.4 percent premium to the stock's Friday closing price. The deal is the latest in a string of multibillion-dollar acquisitions in the U.S. healthcare sector.
Aetna shares rose 4.6 percent to $39.80.
The S&P 500 closed its sixth week of gains on Friday, closing in on four-year highs, as investors wait for the European Central Bank to take steps to control the euro crisis in September. Last week the index broke away from the 1,400 level where it had stalled for much of August.
"You can basically see the light at the end of the tunnel," said Jack de Gan, chief investment officer at Harbor Advisory Corp in Portsmouth, New Hampshire. "We have room ... for the market to trade to 1,500 by the end of the year on the S&P."
The latest edition of Der Spiegel said the ECB is discussing interest rate thresholds for individual euro zone countries with a view to intervening if the premium over German bonds is exceeded. In its latest comments the ECB stopped short of ruling out the report outright.
The Dow Jones industrial average dropped 20.21 points, or 0.15 percent, to 13,254.99. The Standard & Poor's 500 Index fell 1.42 points, or 0.10 percent, to 1,416.74. The Nasdaq Composite Index lost 3.54 points, or 0.12 percent, to 3,073.05.
"There is a better feeling out there that there is a sense of more unity growing within the EU, and it is being backed by the ECB," said Peter Cardillo, chief market economist at Rockwell Global Capital in New York. "Over the next week or so we are looking at 1,435 to 1,450 on the S&P."
CME Group Inc , the biggest U.S. futures exchange operator, said on Monday it was applying to the British Financial Services Authority for approval to open in the middle of next year a London-based market trading currency futures.
Lowe's Cos Inc reported weaker-than-expected quarterly results and cut its profit outlook for the fiscal year as the world's second-largest home improvement chain lost market share to larger rival Home Depot Inc . The shares fell 3.5 percent to $26.85.
Struggling retailer Best Buy Co Inc said its founder, Richard Schulze, has turned down an offer from the board to conduct due diligence in connection with his proposal to take the company private at a valuation of more than $8 billion. The shares fell 6.3 percent to $19.
The global economic outlook is more uncertain now than at the start of the financial crisis in late 2008, Doug Oberhelman, chief executive of Caterpillar , the world's largest maker of construction equipment, said on Monday. Caterpillar's shares lost 0.2 percent to $89.76.