Citigroup's board was locked in talks yesterday in an attempt to halt a crisis of confidence in the troubled financial services group that has seen it lose more than half its market value over the past three days.

As Citi shares plunged by as much as 20 per cent in early trading, people close to the situation said the board would discuss a series of options, including the position of its chief executive, Vikram Pandit, and the sale of some of its businesses or even the whole company.