The European Union on Thursday fined five banks €1.07 billion (Rs 8,400 crore) for colluding to develop strategies in foreign exchange trading, Bloomberg reported. The banks are Citigroup, Royal Bank of Scotland, JP Morgan, Barclays Plc and Mitsubishi UFJ Financial Group Inc.

Citigroup was fined €310.8 million penalty, RBS €249.2 million and JP Morgan €228.8 million. Barclays Plc was fined €210.3 million and Mitsubishi nearly €70 million. Traders for these banks ran two cartels on online chat rooms, the European Commission, which manages the European Union’s daily affairs, said. They exchanged sensitive information and trading plans that helped them to make decisions about buying and selling stocks.

A sixth bank, UBG Group AG, was not fined because it was the first to inform the European Commission about the collusion.

The European Commission said it began its investigation in 2013, BBC reported. “Most of the traders participating in the chatrooms knew each other on a personal basis,” the commission added.

“Foreign exchange spot trading activities are one of the largest markets in the world, worth billions of euros every day,” EU Competition Commissioner Margrethe Vestager said. “These cartel decisions send a clear message that the commission will not tolerate collusive behavior in any sector of the financial markets.”

Vestager added that the behaviour of the banks had “undermined the integrity of the sector at the expense of the European economy and consumers”.