Tony Hayward cashed in about a third of his holding in the company one month before a well on the Deepwater Horizon rig burst, causing an environmental disaster.
There is no suggestion that he acted improperly or had prior knowledge that the company was to face the biggest setback in its history.
His decision, however, means he avoided losing more than £423,000 when BP’s share price plunged after the oil spill began six weeks ago.