BRUSSELS, Jan 22 (Reuters) - UBS, Credit Suisse Group AG and Royal Bank of Scotland are being investigated by EU antitrust regulators for suspected rigging of interest rates linked to the Swiss franc, a person familiar with the matter said on Wednesday.
The European Commission has been looking into the case for about a year now as part of its investigation into the fixing of lending benchmarks.
The source said there were other banks involved. It was not immediately clear which other financial institutions are under investigation.
The EU competition watchdog slapped a record 1.7 billion euro fine on five banks - Deutsche Bank, RBS, JP Morgan, Citigroup, Societe Generale - and UK-based broker RP Martin last month for rigging other benchmarks.