Over the past few years, US prosecutors fined more than a dozen banks $11.8 billion over allegations of collusion and manipulation in the FX market - a case that helped upend the culture of traders sharing "market color" in Bloomberg chatrooms. Those same banks have reached other settlements over behavior tied to the 'FX Cartel' not only in the US, but also in the UK, with the initial round of penalties coming in 2015.

But in what has become an unceasing loop of punishments, prosecutions and fines, not unlike the rate-rigging and the LIBOR manipulation scandal, it's now Europe's turn.

NEU Competition Commissioner Margrethe Vestager on Thursday announced that five banks had agreed to pay fines totaling €1.07 billion ($1.5 billion) after colluding to "rig" currency markets to benefit their trading books.

The UK and the US have already prosecuted FX traders involved in some of the chat rooms, which had names like the "Essex Express n’ the Jimmy" (named for the commuter train many of the traders traveled on) and "Semi Grumpy Old Men", with mixed success. Traders were accused of using chat rooms on their Bloomberg terminals to collude about their positioning.

Barclays, Mitsubishi UFJ Financial Group, Citigroup, RBS and JPM have agreed to pay the fines. Citigroup got hit the hardest - it will pay €310 million ($347.65 million), according to Bloomberg.

The Europeans are investigating other violations, and could bring more fines in the not too distant future. A case in the US involving similar charges is ongoing in the US, the only difference being the US is fining BNP Paribas instead Mitsubishi. The banks in that case have agreed to pay more than $2.8 billion in exchange for a guilty plea.

Swiss bank UBS was exempted from a fine since it was the first to alert authorities to the existence of the chat rooms (it ratted on its rivals), according to CNBC.

In a statement, Vestager said the investigation took six years.

"Companies and people depend on banks to exchange money to carry out transactions in foreign countries. Foreign exchange spot trading activities are one of the largest markets in the world, worth billions of euros every day," EU Commissioner Margrethe Vestager said in a press release Thursday. "Today we have fined Barclays, The Royal Bank of Scotland, Citigroup, J.P. Morgan and MUFG Bank and these cartel decisions send a clear message that the Commission will not tolerate collusive behavior in any sector of the financial markets. The behavior of these banks undermined the integrity of the sector at the expense of the European economy and consumers," Vestager added. The EU investigation that has been ongoing for the past six years revealed that some individual traders from various banks...exchanged sensitive information and trading plans through various online professional chat rooms. "The information exchanges...enabled [the traders] to make informed market decisions on whether to sell or buy the currencies they had in their portfolios and when," the Commission said in its report.

Whatever else happens, the fact that these banks needed to collude to make money makes us question the notion that the slump in the big banks' FICC trading revenues was caused by 'market conditions.' Maybe their traders just aren't as effective without their morning dose of "market color".