Both the Financial Times and Wall Street Journal have reported that Deutsche Bank has put several of its middle-ranking traders based in New York and other American locations on leave and is "cooperating with requests from regulatory authorities".
A number of international banks including Citigroup, UBS, Barclays and RBS have suspended staff as part of investigations into forex trades by a number of international regulators, led by those in Europe and the US. However, no traders have so far been accused of any wrongdoing.
The Wall Street Journal has also reported that officials from two US regulators, the New York Federal Reserve and the Office of the Comptroller of the Currency, have spent "a couple of days" at Citigroup's London offices as part of a "fact-finding" exercise relating to their investigations. The visit has not been made public by the regulators.
The UK's Financial Conduct Authority (FCA) has not announced a formal investigation in relation to forex trading. However, in October it confirmed that it was "gathering information" from market participants "alongside several other agencies".
"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," the FCA said in a statement at the time.