Reports on Bloomberg state that Vikram Pandit, former Morgan Stanley executive, will oversee trading, investment banking and alternative investments.
Randy Barker, a fixed-income executive will also leave the bank and along with Mr Maheras, represents the first high-profile casualties at the bank following its losses.
Mark Batty, an analyst at PNC Wealth Management in Philadelphia, told Bloomberg: "The company could have managed the turbulent credit markets better than it did, and obviously they're making personnel changes to address the problem."
Last week, the bank declared that losses in third quarter profits fell by 60 per cent following the effects of the sub-prime mortgage crisis in the US.
James Forese, head of stock trading, will take up Mr Maheras' position and will assume responsibility for sales and trading.
Citigroup are not alone in firing high-level figures, Merrill Lynch & Co, Bear Stearns and UBS have all announced departures.