Equities on both sides of the Atlantic climbed, lifted by Burger King's talks to buy Tim Hortons and expectations that the European Central Bank moved closer to additional measures to bolster the struggling euro-zone economy.
In late afternoon trading in New York, the Dow Jones Industrial Average added 0.43 percent, the Standard & Poor's 500 index rose 0.50 percent, while the Nasdaq Composite Index gained 0.40 percent.
Earlier in the session the S&P 500 advanced as high as a record 2,001.95.
Gains in shares of JPMorgan Chase and those of Goldman Sachs, last up 1.8 percent and 1.7 percent respectively, propelled the Dow higher.
"European investors came in today with the mindset that we're going to have a more supportive fiscal and monetary policy stimulus, and therefore we ought to see better times ahead in terms of economic growth and corporate earnings," Phil Orlando, chief equity market strategist at Federated Investors, in New York, told Reuters. "Europe is essentially driving the US."
Europe's Stoxx 600 Index finished the session with a gain of 1.1 percent. France's CAC 40 rallied 2.1 percent, while Germany's DAX climbed 1.8 percent.
At the end of this week, reports on euro-zone inflation and unemployment will draw scrutiny as ECB President Mario Draghi signalled his increasing concern about both at the US Federal Reserve's annual central bank symposium in Jackson Hole, Wyoming, last Friday.
"Draghi is going more in the direction of [quantitative easing] and that is helping equity markets today," Karim Bertoni, who helps manage US$3.3 billion at de Pury Pictet Turrettini in Geneva, told Bloomberg News.
It also pushed Germany's two-year note yield below zero, dropping 3 basis points to minus 0.034 percent, after earlier touching minus 0.046 percent, the least since December 2012, according to Bloomberg.
Confidence among business leaders in Europe's engine economy declined again this month, a report showed. The Ifo institute's business climate index fell to 106.3 in August, from 108 in July, sliding for a fourth straight month.
In the US, the latest report on the housing market fell short of expectations, following a string of better-than-expected data last week. New home sales fell 2.4 percent to a seasonally adjusted annual rate of 412,000 units in July, according to the Commerce Department.
"We believe that ongoing volatility in housing will be one factor keeping the Fed from raising rates prematurely," Gennadiy Goldberg, an economist at TD Securities in New York, told Reuters.
Meanwhile, shares of Burger King Wordwide surged, last up 21 percent, after the company said it was in talks to buy Tim Hortons. The new company, which would be the world's third-largest quick service restaurant, would have its headquarters in Canada, where the overall corporate tax rate is lower than in the US.
Shares of Tim Hortons jumped, last up 21.1 percent.
In other merger and acquisition activity, share of InterMune soared, last up 35.3 percent, after it was bought by Roche for US$8.3 billion.
"This acquisition will complement Roche's strengths in pulmonary therapy," Severin Schwan, CEO of Roche, said in a statement.