Reuters reports that the sales and trading unit of the bank is thought to employ about 17,000 people.
Citigroup has agreed to pay $360m to the brokerage estate of Lehman Brothers to resolve a dispute over $1bn in collateral that the investment bank was forced to post in the days leading up to its bankruptcy in 2008.
The news agency also reports that, according to a settlement reached on Friday with the trustee liquidating Lehman Brothers's U.S. brokerage unit, Citigroup will also relinquish its claim to $75m that was contingently paid to the estate at the beginning of the liquidation, court documents showed.
The trustee, James Giddens, filed the claim against Citigroup and its subsidiaries early last year, arguing that the $1bn was obtained under coercion and that the amount should be part of a general asset pool to be divided among creditors in accordance with bankruptcy law.
The American, previously employed by Deutsche Bank AG (DBK) in Moscow as head of equity sales, confirmed by telephone he had departed without elaborating on the reasons. Colville joined the company in September 2010 from Carpathian Capital Management, where he was a fund manager.