Of that, $2.7 billion will be for probes and $800 million will be for restructuring as the bank closes franchises in some markets around the world, according to CNBC.
Corbat expects Citi to be "marginally profitable" in the fourth quarter, the report said.
Shares of Citi were last trading down more than 2%.
Corbat is speaking at the Goldman Sachs 2014 US Financial Services Conference in New York.