NEW YORK (Bloomberg) -- Oil fell from the highest close in more than a week as markets awaited U.S. stockpile data, while the UK referendum on European Union membership remained too close to call.

 

Futures slid as much as 2.5% in New York. U.S. crude inventories probably fell by 1.5 MMbbl last week, yet stockpiles remain elevated at more than 100 MMbbl above the five-year average, according to a Bloomberg survey before an Energy Information Administration report is released on Wednesday. Separate polls showed leads for either side of the UK referendum before the vote on Thursday.

 

“Macro fears are very much in the driver’s seat. A vote to leave will have serious economic repercussions,” Amrita Sen, chief oil economist for Energy Aspects Ltd. in London, said by telephone. “That is the main reason for market jitters.”

 

Oil has advanced more than 80% from the lowest level in 12 years as disruptions from Nigeria to Canada and falling output in the U.S. trimmed a global surplus. Governments and investors around the world are watching the UK referendum amid concern that a so-called Brexit would spark turmoil across global markets. U.S. crude futures had gained 6.8% in the previous two trading sessions amid growing expectations the country would vote to remain in the EU.

 

“Traders remain cautious ahead of Thursday’s vote,” Phil Streible, senior market strategist at RJO Futures in Chicago, said by telephone. Oil prices continue to trade below $50/bbl “on fears over the Brexit vote, although it seems like the chances of Britain staying in the European Union are much greater than in previous weeks.”

 

West Texas Intermediate for July delivery, which expires Tuesday, declined 84 cents, or 1.7%, to $48.53/bbl at 11:34 a.m. on the New York Mercantile Exchange. On Monday, prices rose $1.39 to close at $49.37/bbl, the highest settlement since June 9. Total volume traded was about 17% below the 100-day average. The more-active August contract was 71 cents lower at $49.25.

 

U.S. Stockpiles

 

Brent for August settlement declined by 75 cents, or 1.5%, to $49.90/bbl on the London-based ICE Futures Europe exchange. The contract rose $1.48, or 3%, to $50.65/bbl on Monday. The global benchmark crude traded at a premium of 65 cents to WTI for August.

 

U.S. crude inventories dropped for a fourth week to 531.5 MMbbl through June 10, according to data from the EIA. Drilling activity rose for a third week through Friday, with companies adding nine to boost the total number of U.S. oil rigs to 337, according to data from Baker Hughes Inc.

 

The market is looking at “whether we will see the rig count rise again and there is some speculation we’ll see a few more oil rigs added,” Randy Ollenberger, an analyst at Bank of Montreal’s BMO Capital Markets unit in Calgary, said by telephone. A $50 oil price level “does represent a ceiling in the short-term because we still can’t accommodate much of an increase in activity levels in the United States."

 

Nigerian militants say they "don’t remember" any cease-fire pact, according to an unverified Twitter post. Nigeria’s presidency also said they were “not aware” of a cease-fire with militants targeting oil facilities in the Niger Delta region, Femi Adesina, President Muhammadu Buhari’s spokesman, said by phone. Lagos-based newspaper ThisDay reported earlier that the government had agreed to a 30-day truce with militants including the Niger Delta Avengers, allowing Buhari to come up with plans to develop the region’s economy.