European Union antitrust regulators charged Europe's biggest bank HSBC, U.S. peer JPMorgan and France's Credit Agricole on Tuesday with rigging financial benchmarks linked to the euro, exposing them to potential fines.
The European Commission also said it would charge broker ICAP soon for suspected manipulation of the yen Libor financial benchmark.
U.S. and European regulators have so far handed down some $6 billion in fines to 10 banks and brokerages for rigging the London interbank offered rate (Libor) and its euro cousin Euribor while prosecutors have also charged 16 men with fraud-related offences.
"The Commission has concerns that the three banks may have taken part in a collusive scheme which aimed at distorting the normal course of pricing components for euro interest rate derivatives," the EU competition authority said.
The three banks and ICAP, which refused to settle the case in December, could face penalties of up to 10 percent of their global turnover if found guilty of breaching EU antitrust rules.