Four of the biggest US and eurozone banks were dragged into the Libor scandal for the first time yesterday when the European Commission hit them with fines for their roles in two rate-rigging cartels.

The European competition enforcer levied a record €1.7bn in fines on banks including Deutsche Bank, Société Générale, JPMorgan and Citi. For those four banks, the settlement was the first admission they played a part in a scandal that has rocked global finance and resulted in dozens of traders and several top executives losing their jobs.

Before the Commission imposed its highest ever cartel fine, the five previous settlements involved just one eurozone bank and no US institutions – prompting private claims from UK bankers that some regulators were acting with national bias.