CNBC reports that according to Goldman Sachs’ head of energy research, a nuclear deal between the U.S. and Iran could send energy prices higher — even if it means more supply in the oil markets.

While it appears to be contradictory, a deal that brings Iranian barrels back to the market could actually see oil prices rise, said Damien Courvalin, who is also a senior commodity strategist at the bank.

Talks in Vienna are ongoing as Iran and six world powers — the U.S., China, Russia, France, U.K. and Germany — try to salvage the 2015 landmark deal. Officials say there’s been progress, but it remains unclear when negotiations could conclude and oil prices have been seesawing as a result.

Courvalin explained his rationale. He pointed to how oil prices rose in April after OPEC+ said they would gradually raise output from May by adding back 350,000 barrels a day.

“An increase in production … is announced that is above anyone’s expectations — ours included. And yet prices rally, volatility comes down,” he said.

“Why? Because we lifted an uncertainty that was weighing on the market since last year,” he told.

Investors wondered if OPEC would end up in a price war when it tried to increase production, but the oil cartel presented a “convincing path going forward,” Courvalin said.

“You could argue the same for Iran,” he added. Simply knowing will likely “lift some of that uncertainty.”

“If that announcement comes in the next few weeks, in our view, it actually starts that bullish repricing,” he said at that time.