European antitrust authorities raided the offices of at least three oil companies in three countries as part of an investigation into suspicions of price fixing.
The European Commission, which requested the action, said the raids took place in Norway and in two EU countries and involved several oil and biofuel companies.
Statoil said its office in the southern Norwegian city of Stavanger was raided. Statoil spokesman Jannik Lindbaek Jr. said the company would cooperate with the investigation.
BP, Shell and pricing agency Platts also confirmed their offices had been raided and said they were cooperating with the investigation.
"The Commission has concerns that the companies may have colluded in reporting distorted prices to a price reporting agency to manipulate the published prices for a number of oil and biofuel products" the Commission, which enforces the bloc's antitrust rules, said on its website.
The Commission said it also has concerns that the companies may have prevented others from participating in the price assessment process, with a view to distorting published prices.
"Competition authorities suspect that several companies may have participated in anti competitive agreements" Mr. Lindbaek told Dow Jones Newswires. "In addition, the inspection is about the potential abuse of a dominant position by another company."
The investigation concerns prices provided to Platts, that produces information and benchmark price assessments for energy markets. Mr. Lindbaek said Statoil has been providing Platts with daily price data for crude oil, refined products and biofuels since 2002.
Unlike the market for oil futures, which are visible on public exchanges like the New York Mercantile Exchange (NYMEX), the terms of over the counter oil deals don't have to be made public. The main sources of price are agencies like Platts, which rely on traders to give them details of deals in the market.
"Even small distortions of assessed prices may have a huge impact on the prices of crude oil, refined oil products and biofuels purchases and sales, potentially harming final consumers" the commission said.