Three senior traders at different banks, linked to regulatory probes into the potential manipulation of the currency markets, have been put on leave, according to reports.
Citigroup's head of European spot currency trading Rohan Ramchandani, Standard Chartered's assistant chief dealer in UK capital Matt Gardiner, and JPMorgan's chief dealer in London Richard Usher have all been put on leave, reported Bloomberg citing in-the-know anonymous sources.
It was also reported that none have been suspended or are accused of any wrongdoing.
Swiss, US, Hong Kong and UK financial regulators are investigating instant messaging communications used by traders to see if there is evidence of attempts to manipulate the foreign currency market worth $5tn (£3.1tn, €3.6bn) in daily business.
Spokespeople from Citigroup and Standard Chartered declined to comment, while JPMorgan had not returned IBTimes UK's call for comment at the time of publication.
It has previously been reported that trader Richard Usher would be at the centre of regulators' inquiries over his time at former employer the Royal Bank of Scotland (RBS). The bank has already handed over a number of instant messages to the UK regulator, the Financial Conduct Authority (FCA).
After media speculation, the UK's Financial Conduct Authority confirmed it is investigating the foreign currency market following suggestions that there may have been attempts made to manipulate it by some of the world's largest financial institutions.
Each day, around $5tn changes hands in the world's currency market. It is the largest market in the financial system.
US, Swiss and Hong Kong regulators are reported to have launched their own investigations into allegations of currency market manipulation.
"We can confirm that we are conducting investigations alongside a number of other agencies both in the UK and abroad into a number of firms relating to trading on the foreign exchange (forex) market," said a spokesman for the FCA.
"As part of this we are gathering information from a wide range of sources including market participants. Our investigations are at an early stage and it will be some time before we conclude whether there has been any misconduct which will lead to enforcement action.
"We will not comment further on our investigations."
None of the global regulators have gone into detail over exactly who they are investigating and on what specific allegations.
"Finma is currently conducting investigations into several Swiss financial institutions in connection with possible manipulation of foreign exchange markets," the Swiss regulator said in a statement, adding it is co-ordinating closely with authorities in other countries as multiple banks around the world are potentially implicated.
Honk Kong's Monetary Authority said it is "aware of the [forex market manipulation] allegations. We have been in communications with the relevant overseas regulators and following up with individual banks."
In the US, both the Department of Justice and the FBI have launched a criminal investigation into potential currency market manipulation.