Citigroup, the biggest American financial services company, told investment bankers they must give at least 50 days’ notice before quitting for a rival firm or forfeit their bonuses.

The chief of personnel at Citigroup’s corporate and investment bank, John Donnelly, detailed the rules in a threepage document sent last Thursday to managing directors and directors. The “Employment Termination Notice Policy” will apply to bonuses paid a year from now, a spokeswoman, Andrea Hurst, said.

“It’s unusual,” said Gary Goldstein, chairman and chief executive officer of New York-based Whitney Group, an executive-recruitment firm that specializes in financial services. “Not many firms have a clawback policy on bonuses.”

Citigroup, the no. 1 global underwriter of stock and bond sales in 2005, is making it more difficult for bankers to leave as the company prepares to pay bonuses on January 26. Banking executives usually get most of their compensation in bonuses, and this year’s may set a record.

Wall Street will pay $21.5 billion of bonuses for 2005, according to New York State Comptroller Alan Hevesi. Financial firms in London will hand out about $13 billion, a 16% increase, the Centre for Economics and Business Research estimates.

The average managing director will get about $1.2 million, according to a November report by Johnson Associates, a New York-based compensation consulting firm.

Investment bankers tend to defect to competitors after bonuses are paid. Citigroup’s new rules require directors to give 50 days’ notice if they plan to leave and managing directors 75 days. During the notice period, bankers are banned from soliciting clients for their new employer or trying to entice colleagues to leave.

“If you fail to give a timely notice and receive a bonus that you wouldn’t have otherwise received had you given timely notice, you will be required to repay such bonus,” the policy states.

Citigroup, also based in New York, said it will provide equal notice to managing directors and directors in the corporate and investment bank that it plans to fire. Mr. Donnelly added that notice requirements are “increasingly common” on Wall Street.

Morgan Stanley, the second-biggest securities firm by market value, imposed new rules in November that require three months’ notice from managing directors and six months from members of the firm’s management committee. Violators forfeit the stock portion of their bonus, a spokesman, James Badenhausen, said.