Amid an ongoing probe by regulators on how benchmark rates are set, at least two banks have taken action after internal reviews.
Sources told BT that in the last few months, OCBC Bank and UBS AG have put a few of their employees on forced leave. These employees are on teams that deal with non-deliverable forward (NDF) foreign-exchange contracts, which are over-the-counter derivatives used to hedge or speculate in thinly traded currencies.
This is an area which the Monetary Authority of Singapore (MAS) directed banks to look into last September, to expand the scope of the independent reviews by banks on the rate-setting process.
A source said that at OCBC, the move was made after the bank primarily went through what employees told each other over Thomson Reuters Messenger, a chat programme.
Over at UBS, several people on the bank's NDF team have been put on forced leave, but it was unclear whether they have been accused of any specific wrongdoing, another source said.
Both sources said that the move has demoralised those involved, who were unaware that what they were doing could be illegal.
When contacted, both banks declined to comment.
MAS also declined to comment on the action taken by the banks.
Other banks which set NDF rates, such as Barclays Bank, Citibank and Credit Suisse, also would not be drawn to comment.
There is talk that some traders in other banks were suspended, but subsequently resigned.
BT understands that DBS Bank, which also sets NDF rates, has not suspended any of its traders.