US authorities have reportedly acted against the global head of foreign exchange trading, Mark Johnson, and charged a former colleague.

HSBC's global head of foreign exchange trading, Mark Johnson, has been arrested by US authorities and a former colleague, Stuart Scott, has also been charged, media reports said.

The two traders are accused by the US Department of Justice of using inside information to profit from a $3.5 billion currency deal.

The bank has reportedly said it does not comment on individual employees and active litigation. The BBC said it is co-operating with the Department of Justice's investigation into global currency markets and claims of manipulation.

This publication has contacted HSBC for comment.

Johnson was released on $1 million bail following a court hearing yesterday.

The US Department of Justice accuses the traders of "front-running", the BBC reported. That is misusing confidential information provided by a client who planned to convert $3.5bn into sterling.