Crude oil prices moved sharply higher in early Thursday trading as voters took to the polls to weigh in on British membership in the European Union.

The so-called Brexit vote is underway. British Prime Minister David Cameron and leading European economists have said staying in the EU would be better for the overall economy. Speaking before the U.S. Senate earlier this week, U.S. Federal Reserve Chair Janet Yellen said a vote to exit the EU "could have significant economic repercussions."

A survey of national polls compiled by The Daily Telegraph in London found a narrow edge in favor of staying in the European Union.

European stock markets rallied Thursday, with the FTSE up about 1 percent. Japan's Nikkei index closed up 1.1 percent.

Crude oil prices moved in parallel with global stock trends. The price for Brent crude oil moved up 1.7 percent at the start of the trading day in New York to $50.73 per barrel. West Texas Intermediate, the U.S. benchmark price for oil, gained 1.6 percent to open at $49.90 per barrel.

The rally comes despite trends showing stagnation in the global economy. In her statements on the health of the U.S. economy, International Monetary Fund Managing Director Christine LaGarde said the outlook was good, but issues like income inequality, a decline in productivity and a shrinking labor pool could create obstacles to further growth.

Oil moved lower Wednesday after data from the U.S. Energy Information Administration showed a lower than expected decline in crude oil inventories. EIA reported stockpiles dropped by 917,000, far less than the 5.2 million barrels reported by the industry's American Petroleum Institute.

Geoffrey Craig, an oil futures editor for S&P Global Platts, said in an emailed state the data suggests the market is still favoring the supply side despite some emerging signs of rebalancing.

"The surplus of crude oil stocks relative to a year ago grew to 68 million barrels, up from 63.6 million barrels the week ending June 10," he said. "Crude stocks sit 33 percent above the five-year average for this time of year."