(Bloomberg) -- European Union regulators revealed quirky details as they fined five banks more than $1 billion: the names of the online chatrooms traders used to collude on foreign-exchange trading strategies.

Talking all day on chatrooms called “Three way banana split” and “Semi Grumpy Old Men,” bankers at rival outfits exchanged banter but also commercially sensitive information, according to investigators.

The colorful chatroom names were disclosed as part of EU fines totaling 1.07 billion euros ($1.2 billion) against five banks for colluding on FX rates. Citigroup Inc. was fined 310.8 million euros, Royal Bank of Scotland Group Plc was fined 249.2 million euros and JPMorgan Chase & Co. will pay 228.8 million euros.

The EU also said on Thursday that one chatroom was called “Essex Express ‘n the Jimmy” because all the traders apart from one named James lived in Essex and met on a train to London.

Occasionally, the bankers engaged in a practice known as “standing down” where some of them would temporarily refrain from trading to avoid interfering with another member of the chatroom, according to the European Commission.

Traders’ manipulation of benchmark foreign-exchange rates was exposed in 2013, triggering regulatory probes in the U.S., the U.K. and Switzerland. More than a dozen financial institutions have paid about $11.8 billion in fines and penalties globally, with another $2.3 billion spent to compensate customers and investors.

To contact the reporter on this story: Gaspard Sebag in Paris at gsebag@bloomberg.net

To contact the editors responsible for this story: Anthony Aarons at aaarons@bloomberg.net, Peter Chapman

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