Barclays is heading the FTSE's fallers today, down around 12%.
The bank has announced a trio of departures, headed by deputy chairman Sir Nigel Rudd, who will leave the board at the annual general meeting in April.
Two Barclays Capital executives - Jack Malvey, the head of total-return strategy, and Serkan Bektas, the managing director of UK solutions and structured product sales - are also leaving.
Barclays shares have fallen 11.6% to 163.2p.
All the banks are suffering today, reversing gains yesterday when there was more optimism about what the government might do to provide additional support to the sector.
They have also taken their cue from big falls in the share prices of US giants Citigroup and Bank of America last night.
Royal Bank of Scotland, which is now 58%-owned by the government, slipped 6.6% to 51.4p amid reports that it is selling its stake in Bank of China.
Merger partners Lloyds TSB and HBOS are both down, with Lloyds sliding 6.4% to 131.7p and HBOS losing 6.8% to 78.4p.
The two banks will combine to become Lloyds Banking Group next week, with a 43% stake to be held by the government.
The FTSE is now down 94.3 points to 4331.89, taking the blue-chip index's losses over the last five days.
