Any confirmed manipulation of oil prices would have caused "huge" damages for consumers and the case has similarities to the Libor benchmark scandal, the European Union's top antitrust regulator said Tuesday. EU antitrust authorities carried out unannounced inspections of energy companies BP PLC (BP), Royal Dutch Shell PLC (RDSA) and Statoil ASA (STO) this month as part of a probe into whether they manipulated prices in the $2.5 trillion physical-oil market by giving false data to an oil index publisher, the Platts unit of McGraw Hill Financial Inc. The offices of Platts were also inspected
Any confirmed manipulation of oil prices would have caused "huge" damages for consumers and the case has similarities to the Libor benchmark scandal, the European Union's top antitrust regulator said Tuesday.

EU antitrust authorities carried out unannounced inspections of energy companies BP PLC (BP), Royal Dutch Shell PLC (RDSA) and Statoil ASA (STO) this month as part of a probe into whether they manipulated prices in the $2.5 trillion physical-oil market by giving false data to an oil index publisher, the Platts unit of McGraw Hill Financial Inc. The offices of Platts were also inspected.

"If...the manipulation is confirmed, indeed, huge damages for consumers and users would have been originated by this," Joaquin Almunia, European Commissioner for competition, said at a European Parliament hearing in Brussels. "To some extent, this problem has similarities with the benchmarks in the financial sector and with the investigations we are carrying out on Libor, Euribor and Tibor cases."

Index-publishing companies such as Platts derive their prices from self-reported transaction data from participants in deals. It isn't clear whether Platts is a target of the probe, nor whether the investigation is limited to those four companies. Representatives of the oil companies and Platts have said they are cooperating with authorities.

Mr. Almunia said the Commission is investigating both infringements of anti-cartel laws and the possible abuse of dominant market positions as part of its probe.

However, he stressed that the investigation is still at an early stage. "We are still starting the analysis of the information we obtained, [and] we will adopt a decision to launch a formal investigation" if manipulation is confirmed, Mr. Almunia said.