Oil traded near its highest level since 2015 on Wednesday, having risen above $67 a barrel during the previous session. The sustained strength came after hedge funds placed a record bet that Brent crude’s near 35 per cent rally over the past six months will continue into the new year, with protests in Iran stoking buying. While Iran’s oilfields have so far been unaffected by the largest protests against the Islamic regime in almost a decade, traders said renewed risks in Opec’s third-biggest producer had added to momentum as prices test new peaks.

“Geopolitical risks are clearly back on the crude oil agenda after having been absent almost entirely since the oil market ran into a surplus in the second half of 2014,” said Bjarne Schieldrop at Nordic bank SEB. “Geopolitical risks started to impact the oil price again last autumn as production cuts then had drawn inventories significantly lower.” Brent crude oil, the international benchmark was at $66.55 a barrel in early Wednesday trade, leaving it within touching distance of Tuesday’s intraday high of $67.29.

The rally in prices since June has come as Opec-led production curbs designed to end a three-year-old oil glut have helped tighten the market. Prices had crashed from above $100 a barrel in 2014 as US shale production swamped the industry, leading the cartel to ultimately align with Russia in pursuing production curbs to drain stocks and raise the price. The Opec and Russia-led curbs, which they have agreed to extend throughout 2018, have set up a potential showdown with the US shale industry now prices are back above $60 a barrel.