BRUSSELS-- J.P. Morgan was fined more than EUR72 million by European Union regulators Tuesday for rigging a benchmark interest rate and operating a separate cartel in derivatives linked to the Swiss franc.

Two other banks, Credit Suisse Group AG and UBS AG, were also fined by the EU for operating a cartel for Swiss franc derivatives.

Royal Bank of Scotland Group was involved in both cartels but escaped fines because it revealed their existence to the European Commission, the EU's central antitrust regulator, the Commission said.

The fines represent the latest stage of a series of probes by the EU into alleged market abuse by financial institutions.

"We have imposed total fines of about EUR94 million on four major international banks who violated EU antitrust rules," EU antitrust chief Joaquín Almunia said in a statement.

The fines are small in comparison with the record EUR1.71 billion fine against six financial companies handed down in December by the EU, which accused them of operating cartels to rig the yen London interbank offered rate and the euro interbank offered rate, or Euribor.

Write to Tom Fairless at tom.fairless@wsj.com

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