The New York Mercantile Exchange conceded on Thursday that establishing a strong presence in the Brent crude futures market in London was becoming more difficult as it awaited regulatory approval, while volumes continued to rise at its electronic rival, the International Petroleum Exchange.

Nymex plans to open an open-outcry exchange in London to try and wrest control of trade in Brent futures away from the IPE, which closed its trading floor in early April. In the interim, Nymex has established a Brent futures trading hub in Dublin with mixed success.