Bank of America, Barclays, Citigroup, Credit Suisse, UBS, Standard Bank, Royal Bank of Canada, Standard Chartered, and Royal Bank of Scotland declined to comment. Nomura, JPMorgan, Deutsche Bank, Standard Bank, Tokyo-Mitsubishi and HSBC did not have an immediate comment.
In the current probe, Cade said traders who described themselves as "The Cartel" or "The Mafia" used online chat rooms to fix their positions ahead of market trades. Another 30 individuals that might have participated in the scheme are also under investigation, the watchdog said.
At least one of the alleged participants is cooperating with the current investigation, Cade said. The document made available by Cade did not specify how much money the banks or the individuals cited in the investigation made with the scheme.
The Cade document said traders probably front-ran client orders and pushed through trades that affected the way benchmarks like Brazil's PTax and WM/Reuters rates were set. They might have also colluded to fix spreads on client trades, unveil spot and future trades that should have been kept confidential and even deal flow volume data, the document added.
Benchmarks like the PTax or the WM/Reuters are used by investment firms to value their assets on a day-to-day basis.
The trades were shared and discussed in online chats through Bloomberg terminals, Cade said. Bloomberg LP and Thomson Reuters Corp, the parent company of Reuters News, compete in the financial information market, providing analytical and communication tools for investment professionals.
Both Bloomberg and Thomson Reuters declined to comment on the Cade investigation.
The real gained 1.6 percent to 3.0991 reais to the dollar on Thursday. Traders said the Cade probe had no impact on currency prices.