Citigroup chief executive Vikram Pandit has surprised Wall Street by resigning with immediate effect.

Unconfirmed sources say it may have been linked to a regular board meeting, discussing quarterly results between Pandit and Chairman Michael O' Neil that got a little heated. With O' Neil criticizing Pandit for being too detached from the bank's day-to-day operations and told him to get more involved ,a statement perhaps prompted by figures released that show an 88% drop in quarterly profits to $468m (£291m). In response Pandit decided to resign and O'Neill did not stop him.

This move prompted John Havens, the bank's chief operating officer and a close friend of Pandit who had been thinking of leaving for some time, to jump ship as well.

In light of Pandit's departure the board announced the appointment of Michael Corbat as CEO, who had previously been head of Europe, Middle East, and Africa whose experience is likely to prove valuable as a new round of stronger regulations for financial firms approaches.

Written and presented by Ann Salter