The other three lenders are Royal Bank of Scotland, UBS and a small Japanese bank, the people said. The banks will see a 10 percent cut in their fines for admitting wrongdoing.

In contrast, Credit Suisse, which has previously said it did not find any evidence of misconduct, is fighting the EU antitrust charge. It is not clear if the European Commission will be able to finalise the case in time to levy a fine against the Swiss bank in coming weeks.

The EU antitrust enforcer, which has been investigating the case over the last six years and could hand out fines up to 10 percent of a company's global turnover for breaching EU rules, declined to comment.

Barclays, Citigroup, JPMorgan, Royal Bank of Scotland and HSBC declined to comment.

It is possible the EU could space out its rulings against the banks over several weeks rather than lump them together in one day, the sources said.

Barclays, BNP Paribas, Citigroup, JPMorgan, Royal Bank of Scotland and UBS have entered related guilty pleas in a U.S. case, and been collectively fined more than $2.8 billion (£2.15 billion).

U.S. regulators said the foreign exchange rate rigging was allegedly done through chat rooms with such names as "The Cartel," "The Mafia" and "The Bandits' Club," through tactics with such names as "front running," "banging the close," "painting the screen" and "taking out the filth."

(Reporting by Foo Yun Chee, additional reporting by Sinead Cruise and Lawrence White in London, Lauren LaCapra in New York; Editing by Francesco Guarascio and Mark Potter)

By Foo Yun Chee