The investigation, which involves 15 of the world's largest banks, began following the presentation of evidence by UBS, Valor Economico reported, without naming its sources.
A UBS press representative did not immediately respond to a request for comment.
In a document released Thursday, antitrust watchdog Cade alleged the banks colluded to influence benchmark currency rates in Brazil by aligning positions and pushing transactions in a way that deterred competitors from the market between 2007 and 2013, at least. Foreign exchange trading in Brazil is estimated at about $3 trillion a year, excluding swaps and derivative transactions.
The banks named in the Cade probe are Bank of America Merrill Lynch, Bank of Tokyo-Mitsubishi UFJ, Barclays Plc, Citigroup Inc, Credit Suisse Group AG, Deutsche Bank AG, HSBC Holdings Plc, JPMorgan Chase & Co, Morgan Stanley, Nomura Holdings Inc, Royal Bank of Canada, Royal Bank of Scotland Group, Standard Bank Group Ltd, Standard Chartered Plc and UBS.
(Reporting by Asher Levine; Editing by Jeffrey Benkoe)