“Efforts to manipulate the European oil indices, if proven, may have already impacted US consumers and businesses, because of the interrelationships among world oil markets and hedging practices,” Senator Ron Wyden, the chairman of the Senate Energy and Natural Resources Committee, wrote in a letter to Attorney General Eric Holder.
The Commodity Futures Trading Commission and Federal Trade Commission are yet to comment on the role they might play in the probe.
Last week authorities raided the Canary Wharf office of pricing agency Platts, and the offices of Statoil, Royal Dutch Shell and BP in the biggest cross-border action since the probe into rigging of Libor benchmark interest rates.
At issue is whether there was collusion to distort prices of crude, refined oil products and ethanol traded during the Platts market-on-close (MOC) system – a daily half-hour window in which it sets prices.
The European Commission is also examining whether companies were prevented from taking part in the price assessment process.