Apparently, yesterday was Citigrooup chief executive Chuck Prince's fourth anniversary in the top job. And what a day - the bank announced that it had suffered $6bn of writedowns and losses in Q3 due to turbulence in the credit markets. Many analysts are calling for his head.

Meanwhile, European banking giants Credit Suisse and UBS both issued profit warnings, with UBS announcing a Q3 loss of between £250m and £334m.

Not surprisingly, UBS took action and announced 1,500 job cuts. As part of the shakeup, chief financial officer, Clive Standish, will retire.

We can't help wondering if this is just the tip of the iceberg...