The offices of several firms involved in the oil market have been raided by European Commission officials. The commission said these companies may have colluded in reporting distorted prices. It did not name the firms, and said the raids do not mean the companies were guilty of any charges. BP, Royal Dutch Shell, Norway's Statoil and the pricing agency Platts confirmed that they are working with the authorities in their inquiries. The investigation relates to the pricing of oil, refined products and biofuels. As part of the investigation, the Commission said it is examining whether the companies may have prevented others from participating in the pricing process with a view to distorting published prices. It added that 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. The EU called the raids unannounced inspections. They are seen as a preliminary step in an investigation into suspected anti-competitive practices.