The US Justice Department is looking to fine four banks RBS (LSE: RBS.L – news) , Barclays (LSE: BARC.L – news) , Citigroup (NYSE: C – news) and JP Morgan Chase to settle accusations of criminal activity in the currency markets

Royal Bank of Scotland and Barclays are facing penalties of about $ 1bn (£662m) each from US authorities for their alleged role in the manipulation of currency markets.

The US Justice Department is looking to fine four banks RBS, Barclays, Citigroup and JP Morgan Chase to settle accusations of criminal activity in the currency markets.

In total the US authorities are seeking penalties of about $ 4bn, with some banks being asked for more and some less than $ 1bn depending on their early cooperation with investigations, according to a report from Bloomberg.

However, final penalties could be lower as banks are pushing back harder than in some previous negotiations, the report added.

Prosecutors will be forcing Barclays, Citigroup, JPMorgan and the Royal Bank of Scotland to plead guilty as part of the settlement, people familiar with the matter told Bloomberg.

UBS (NYSEArca: FBGX – news) has been granted immunity from prosecution, as it was the first bank to notify US authorities of possible misconduct in the foreign-exchange market.

The banks have already agreed to pay regulators about $ 4.3bn for their involvement in the rigging of currency rates.

The banks have been fined a total of £1.1bn by the FCA and $ 1.5bn (£933m) by the US Commodities and Futures Trading Commission (CFTC).

At the same time, the Swiss Financial Markets Supervisory Authority announced a 134m Swiss franc (£88m) fine on UBS, and the US Office of the Comptroller of the Currency announced an additional $ 950m in fines on Citibank, JPMorgan and Bank of America (Swiss: BAC.SW – news) .

In total, the fines reached £2.74bn. The banks themselves were not fined for currency manipulation, but rather for failing to manage staff.

Meanwhile, the banks under investigation are setting aside big amounts as legal reserves. Barclays reserved £750m for the currency settlement in the fourth quarter, bringing its total to £1.25bn.

RBS took a £1.2bn charge in the same period for conduct and litigation, including a £320m provision for US currency-rigging probes.

JPMorgan Chase set aside an additional $ 1.1bn, pre-tax, for legal expenses in the fourth quarter, while Citigroup added $ 2.9bn in the fourth quarter for legal matters. UBS set aside $ 175m for legal charges in the fourth quarter.