That reputation for safety was no doubt shored up psychologically by the maintenance of a fixed share price.

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An option to buy their companies' shares at a fixed price gives directors an incentive to push up the share price, bringing the interests of management and shareholders more closely into line.

ECONOMIST: Spare a thought for shareholders

The share price has no theoretical ceiling, while the bonds pay a fixed amount.

ECONOMIST: Investment: In search of those elusive returns | The