JP Morgan Chase, the largest bank in the US, has revealed it is under investigation over currency trading.
The firm said the US Department of Justice (DoJ) had launched a criminal investigation, while other regulators are running civil investigations.
It added that possible losses from all its the legal proceedings could total $5.9bn (£3.7bn).
A number of other banks, including HSBC, RBS and Barclays, have recently set aside sums to cover similar probes.
Global lenders, such as Citigroup and UBS, are also being investigated over the alleged rigging of foreign-exchange rates.
In a filing with the Securities and Exchange Commission (SEC) on Monday, JP Morgan said that it was co-operating with authorities, and currently engaged in discussions aimed at “resolving their respective investigations”.
But, the firm added, “there is no assurance that such discussions will result in settlements”.
As well as the criminal investigation by the DoJ, JP Morgan revealed it also faces civil investigations by the Commodity Futures Trading Commission (CFTC), the UK’s Financial Conduct Authority (FCA) and “other foreign government authorities”.
Last year, JP Morgan Chase agreed to a record $13bn settlement with US authorities for misleading investors during the housing crisis.