U.S. and European stocks jumped Thursday as investors appeared to bet that voters in the U.K. will choose to remain in the European Union in a historic referendum that could have global financial repercussions.

The stock rally sent the Standard & Poor’s 500 index up 27.87, or 1.3%, to 2113.32, leaving it just 0.9% shy of its record high. The Dow Jones industrial average rose 230.24 points, or 1.3%, to 18,011.07 And the Nasdaq composite index gained 76.72, or 1.6%, to 4910.04.

That came on the heels of a rally in European markets that lifted Britain's FTSE 100 1.2%, France’s CAC-40 2.0% and Germany’s DAX 1.9%. Also, the British pound rose 1.2% and hit its highest level this year. The British pound was up more than 1% to $1.4882, the highest level so far this year.

Investors are anxiously awaiting the outcome of the vote as analysts predict a vote to leave the EU would send global stocks tumbling due to the economic uncertainty a U.K. exit would create.

Ahead of the vote, a new Ipsos Mori poll completed Wednesday night showed the "remain" supporters with a narrow lead — 52% to 48%. But the polling firm’s chief executive, Ben Page, said 13% of those polled said they still might change their minds. Another poll, from Populus, gave "remain" 55% and "leave" 45%.

Asian markets were mixed, with Japan’s Nikkei 225 gaining 1.1% to finish at 16,238.35 and Hong Kong’s Hang Seng index gaining 0.4% to 20,868.34. The Shanghai composite fell 0.5% to finish at 2891.96.