(Adds comments from banks)
ZURICH, June 6 (Reuters) - Five banks have been fined a total of 90 million Swiss francs ($90.5 million) for colluding to rig the multi-trillion dollar foreign exchange market, Switzerland's competition authority said on Thursday.
The Swiss fines come on top of 1.07 billion euros ($1.20 billion) of fines handed out last month by the European Union.
Barclays, Citigroup, JP Morgan and Royal Bank of Scotland were all punished by the Swiss authority, known as WEKO. It said it found "several anti-competitive arrangements between banks in foreign exchange spot trading".
Also punished was Japan's MUFG Bank for its part in the scam which involved traders coordinating their activities through internet chatrooms.
Traders from Barclays, Citigroup, JPMorgan, Royal Bank of Scotland and UBS participated in the so-called 'Three way banana split' cartel from 2007 to 2013, WEKO said. Participants in the 'Essex express' cartel which ran from 2009 to 2012 were traders from Barclays, MUFG Bank, RBS and UBS.
Barclays was fined 27 million francs, Citigroup 28.5 million francs, JPMorgan 9.5 million francs, MUFG Bank 1.5 million francs and RBS 22.5 million francs.
UBS was not punished because it revealed the cartels to the competition authorities first, while an investigation is still underway into Credit Suisse. WEKO said it had closed its investigation into Julius Baer and Zuercher Kantonalbank.
"Credit Suisse is continuing to cooperate fully with WEKO's investigation process and intends to vigorously contest the substance of the allegations," a spokesman for the Swiss bank said.
JP Morgan, Barclays and RBS declined to comment, while Citi was not available for comment. ($1 = 0.8906 euros) (Reporting by John Revill and Silke Koltrowitz; Editing by Elaine Hardcastle)