Better-than-expected Chinese data and takeover deals helped bolster Wall Street, which also welcomed a Russian proposal to put Syria's chemical weapons under international control in an effort to avert US military intervention.
Shares of Molex soared, last up 31.6 per cent, after Koch Industries agreed to buy the maker of electronic components for US$7.2 billion. In other deals, Ares Management and the Canada Pension Plan Investment Board reached agreement to buy Neiman Marcus, an American luxury retail chain, for US$6 billion.
"There is a nice parade of deals and that is always suggestive of a healthy market," Quincy Krosby, market strategist at Prudential Financial in Newark, New Jersey, told Reuters.
Oil prices fell as concern about the Syrian conflict escalating eased after President Bashar al-Assad's government welcomed a Russian proposal to place its chemical weapons under international control. The suggestion comes a day before US President Barack Obama is scheduled to present an Oval Office address seeking support for American military action to oust Assad.
"The delays in agreeing to any action in Syria are sending Brent lower and WTI is along for the ride," Bill O'Grady, chief market strategist at Confluence Investment Management in St Louis, told Bloomberg News. "The president has a tough row to hoe. The ramifications of him not getting a yes vote are pretty big."
Also helping sentiment were further signs of recovery in the China, the world's second-largest economy, as the nation's exports grew more than expected in August.
In late afternoon trading in New York, the Dow Jones Industrial Average climbed 1.03 per cent, as did the Standard & Poor's 500 Index, while the Nasdaq Composite Index rallied 1.3 per cent.
Meanwhile, Federal Reserve Bank of San Francisco President John Williams said the central bank will probably adopt a "multi-step" plan for easing back its pace of bond buying as the jobs market has improved in line with expectations.
"We're still on our forecast, in my view, that we would begin tapering, quote-unquote, later this year," Williams told reporters after a speech to the National Association for Business Economics in San Francisco, according to the Wall Street Journal. "I'm not going to get into whether that's September, or whatever."
Carl Icahn said on Monday he was withdrawing from a battle to thwart founder Michael Dell's proposed buyout of Dell, saying it would be "almost impossible to win". Shareholders are set to vote on the buyout on September 12. Shares of Dell were last steady, edging 1 US cent higher to US$13.85.
In Europe, the Stoxx 600 Index closed with a 0.1 per cent slide from the previous close. France's CAC 40 fell 0.2 per cent, and the UK's FTSE 100 Index shed 0.3 per cent. Germany's DAX eked out a gain of less than 0.1 per cent.