The pressure on Chuck Prince to improve Citigroup's performance increased sharply yesterday after Prince Alwaleed bin Talal, the company's biggest shareholder, declared that costs were out of control and investors' patience was wearing thin.

The Saudi prince, who has been increasingly critical of Citigroup's performance, called for "draconian" measures to curb expenses. "I'm a shareholder in alliance with Citigroup. I'm patient but enough is enough," he said.