In January 2009, Steve Jobs, chief executive of Apple, sent a short letter to the “Apple community” telling them he had lost weight due to a “hormonal imbalance”. The prior year, while running for the presidency, Senator John McCain released 1,173 pages of medical records detailing his health including his fight with melanoma. Apple recently announced record, non-holiday quarter, revenues. John McCain lost. So when does a leader require a sick note?

The issue of Mr Jobs’ health has raised serious questions in the US about a business leader’s rights to privacy and investors’ rights to material information about the companies – and management teams – in which they invest.