Royal Bank of Scotland and Barclays are among a raft of global banking giants involved in a record 1.7 billion euro (£1.4 billion) settlement with European regulators in the latest rate-rigging crackdown.
Eight banks have agreed penalties with the European Commission over allegations they formed cartels to fix two key benchmark interest rates used to set the price of trillions of dollars of financial products, from mortgages to complex financial products.
RBS will pay 391 million euros (£325 million) for its role in the attempted rigging of the Yen Libor and Euribor - the Tokyo and euro area equivalents of the London interbank offered rate (Libor).
But Barclays is immune from a potential 690 million euro (£573 million) penalty after blowing the whistle on the Euribor cartel.
The sanctions - the first from the EC on rate manipulation - are the highest yet for European antitrust enforcement.