The unusual action from the US office comes in the wake of a number of embarrassing regulatory setbacks for Citigroup, which included being forced to close its private banking operations in Japan due to legal breaches, last year’s WorldCom and Enron troubles and the current ongoing investigations in Europe over irregular bond trading.

However, Chuck Prince, Citigroup’s chief executive, has played down the significance of the guidance issued by the US Federal Reserve Board, stating that the company, although built on acquisitions and mergers, is now focused on organic growth through growing its existing businesses.

Meanwhile, Prince has implemented a five-point plan to improve ethical standards and avoid more regulatory problems. The plan will involve retraining the bank’s staff in industry ethics and legal matters in the hope that regulatory confidence can be restored.