UPDATE 1-UBS, RBS, Credit Suisse in EU Swiss franc interest rate probe -source

Wed Jan 22, 2014 1:12pm EST

By Foo Yun Chee

BRUSSELS Jan 22 (Reuters) - UBS, Credit Suisse 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 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 were under investigation.

Commission spokesman for competition policy, Antoine Colombani, said: "Our investigation is ongoing. We have no further comment."

RBS, UBS and Credit Suisse declined to comment.

The EU competition watchdog imposed 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.