Royal Bank of Scotland has suspended another trader as part of its ongoing investigation into the potential manipulation of Libor

Royal Bank of Scotland has suspended another trader as part of its ongoing investigation into the potential manipulation of Libor.

The bailed-out bank has already warned that it expects to be fined by regulators for its role in attempting to fix the key benchmark interest rate which has cost Barclays £290m in penalties.

RBS fired four traders last year – including Tan Chi Min, a senior trader in Singapore who is now suing the bank for wrongful dismissal – and earlier this month suspended Jezri Mohideen as head of rates trading for Europe and Asia Pacific.

It has now been reported that Ken Choy, a Singapore-based foreign exchange trader, has also been suspended as the local authorities step up an investigation into the local interest rate benchmarks. Choy was quoted in the Wall Street Journal as saying he was on “compliance leave”.

RBS, 81% owned by the taxpayer, is expected to face fresh questions about Libor when it reports its third quarter figures next week and repeated its statement that it was continuing to co-operate with regulators.

The other bailed-out bank, Lloyds Banking Group, is also co-operating with regulators after receiving subpoenas from a number of jurisdictions, including the US.

“It is currently not possible to predict the scope and ultimate outcome of the various regulatory investigations or private lawsuits, including the timing and scale of the potential impact of any investigations and private lawsuits on the group,” Lloyds said in its half year results in the summer. It will update the market on its third quarter trading next week amid concerns it could also be forced to make a new provision for payment protection insurance misselling on top of the £4.3bn already set aside to cover potential claims.

Eric Schneiderman, New York attorney-general and George Jepsen, the Connecticut attorney-general, are among the two US bodies to request information from banks lately. More than a dozen banks around the world are thought to be co-operating with regulators in the UK, Europe, the US, Switzerland and in Asia.