The former head of Citibank's energy-derivatives trading desk inflated trading profits by entering bogus data into the bank's computer model in a bid to improve his job prospects and boost his bonus.
David Becker, 40, of New York, pleaded guilty to charges of conspiring to falsify bank records and commit wire fraud and faces up to five years' in prison and a fine of $250,000.
Becker, along with an accomplice, overstated the financial performance and understated the market risk of Citibank's commodities desk in the autumn of 2003 through January 2004, in part by entering phoney data into a computer model to make it appear as though the bank was taking on less market risk.
At one point in autumn 2003, the profit and loss of the energy-derivatives desk was overstated by $20m.
Prosecutors say that Becker was trying to improve his his job performance and his eligibility for bonuses from Citibank.