This paper examines the self-interested reasons that businesses can have for ethical behaviour. It distinguishes between economic and non-economic reasons and, among the latter, notes those connected with the self-esteem of managers. It offers a detailed typology of prudential reasons for ethical behaviour, laying particular stress on those to do with avoiding punishment by society for wrongdoing and, more particularly still, stresses the role of campaigning pressure groups within that particular category of reasons. It goes on to suggest that because (...) of their occupation of the moral high ground, campaigning groups are well placed to damage the self-esteem of managers and that this is why those groups seem able to exert an influence that goes beyond their somewhat limited capacity to inflict economic damage upon businesses. The paper concludes with the suggestion that we may be witnessing a virtuous spiral whereby rising public expectations of morality in business lead to ever increasing moral commitments by business that then cause those expectations to rise still further. (shrink)