The European Commission released a statement on Tuesday confirming its “officials carried out unannounced inspections at the premises of several companies active in and providing services to the crude oil, refined oil products and biofuels sectors”.

It said: “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.

“Furthermore, the Commission has concerns that the companies may have prevented others from participating in the price assessment process, with a view to distorting published prices. Any such behaviour, if established, may amount to violations of European antitrust rules that prohibit cartels and restrictive business practices and abuses of a dominant market position (Articles 101 and 102 of the Treaty on the Functioning of the EU and Articles 53 and 54 of the EEA Agreement).

“The prices assessed and published by Price Reporting Agencies serve as benchmarks for trade in the physical and financial derivative markets for a number of commodity products in Europe and globally. 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 EC said there is no legal deadline to complete inquiries into anticompetitive conduct. The duration depends on the complexity of each case, the extent to which the companies concerned co-operate with the Commission and the exercise of the rights of defence.