Oil traders should expect prices to pullback by at least 15 percent over the coming months, according to a senior analyst at Commerzbank.

Oil prices rose to their highest levels since mid-2015 on Wednesday amid political unrest in Iran, despite analysts saying there was little risk of supply disruption from OPEC’s third largest producer. And while long positions have skyrocketed, short positions — or bets that prices will fall — have dipped to their lowest levels since February in recent weeks.

The oil price rally is “definitely due to massive overheating of the speculators and is likely to correct over the next month,” Eugen Weinberg, head of commodities research at Commerzbank, told CNBC on Friday.

“(I expect) the price of oil to correct by at least 10 to 15 percent over the coming months because the current fundamentals are not justifying this kind of strength,” Weinberg said.

Oil prices retreated from their highest level in 2.5 years on Friday as surging U.S. production appeared to offset supply fears stoked by anti-government rallies in Tehran. Brent crude traded at $67.38 a barrel at around 12 p.m. London time (7 a.m. ET), down 1 percent, while U.S. crude was seen at $61.41, down 0.9 percent.

While most asset classes recorded gains in 2017, Weinberg said the commodities sector had been held back by a combination of monetary policy decisions and geopolitical factors. Nonetheless, he argued the most important component for commodities at the beginning of 2018 was investment activity.

Speculative bets that U.S. crude prices will rise have surged since September as OPEC and 10 other allied producers, including Russia, secured a deal to continue capping their oil production. The agreement has helped to clear a global supply overhang and drain stockpiles of crude oil.

In December, Goldman Sachs and Morgan Stanley both raised their respective oil price forecasts, citing a stronger-than-anticipated OPEC-led commitment to extend output cuts. The cuts, which started in January 2017, are poised to continue through all of 2018.

The price of oil collapsed from almost $120 a barrel in June 2014 due to weak demand, a strong dollar and booming U.S. shale production. OPEC’s reluctance to cut output was also seen as a key reason behind the fall. But, the oil cartel soon moved to curb production — along with other oil producing nations — in late 2016.