Continental itself would feel few ill effects from the collapse of its now-biggest shareholder, because the two firms' financing and operations are not yet integrated.

Over the past year bank supervisors, central bankers and national treasuries have queued up to bail out European Banks' shareholders and bondholders in a bid to avert panic.

Although the rules expressly prohibited using the funds for dividend payments or stock buybacks, subsequent analysis has shown participants sent most of it to shareholders anyway.