Equities on both sides of the Atlantic jumped after polls indicated Democratic candidate Hillary Clinton is on track to clinch the US presidential election.
Clinton is ahead of Republican rival Donald Trump, 44 per cent to 41 per cent, when third-party candidates are included, according to the final Bloomberg Politics national poll before Tuesday's election. At least five major polls on Monday showed Clinton in the lead, according to Reuters.
The FBI on Sunday said it has no reason to pursue criminal charges against Clinton over the handling of her emails, lifting a cloud that it had placed on her campaign a little more than a week ago.
In 12.54pm trading in New York, the Dow Jones Industrial Average rallied 1.9 per cent, while the Nasdaq Composite Index climbed 2.3 per cent. In 12.39pm trading, the Standard & Poor's 500 Index gained 2 per cent.
"We've been down nine straight days as concerns over a potential Trump victory put a lot of caution in the market," Michael James, managing director of equity trading at Wedbush Securities in Los Angeles, told Bloomberg.
"Some of that is being relieved with the comments from the FBI about the Clinton e-mail investigations."
The Dow climbed, led by advances in shares of UnitedHealth Group and those of Microsoft, up 3.3 per cent and 3 per cent respectively.
In early afternoon trading all 30 members of the Dow traded higher.
The US dollar also strengthened, as a Clinton victory underpins expectations the Federal Reserve will raise interest rates at next month's meeting.
"Our base case is that Clinton wins and the [US] dollar strengthens" into the Federal Reserve meeting in December, Robert Rennie, head of financial-markets strategy in Sydney at Westpac Banking Corp, told Bloomberg. "Clearly, markets appear to have embraced that view today."
In Europe, the Stoxx 600 Index finished the day with a 1.5 per cent gain from the previous close. The UK's FTSE 100 Index added 1.7 per cent, Germany's DAX Index jumped 1.9 percent, while France's CAC 40 Index also increased 1.9 per cent.
We've been down nine straight days as concerns over a potential Trump victory put a lot of caution in the market.
Banks advanced, bolstered by gains in shares of HSBC Holdings as Europe's largest bank posted better-than-expected earnings. The stock closed 4.6 per cent higher in London.
Meanwhile, OPEC said Russia, the world's biggest energy producer, was "on board" with an OPEC agreement to curb crude oil production.
"We as OPEC,remain committed to the Algiers accord ... we remain committed to the implementation," Secretary-General Mohammed Barkindo said on the sidelines of the Abu Dhabi International Petroleum Exhibition & Conference, according to media reports.
"I have heard from the highest quarters in Moscow that Russia is on board," according to Barkindo.