| This paper examines the role of vulnerability in the basis of business ethics by criticizing its role in giving a moral substantial character to fiduciary duties to shareholders. The target is Marcoux’s (Bus Ethics Q 13(1):1–24,2003) argument for morally substantial fiduciary duties visa’-vis the multifiduciary stakeholder theory. Rather than proceed to support the stakeholder paradigm, a conception of vulnerability is combined with Heath’s 2004) ‘‘market failure’’ view of the ethical obligations of managers as falling out of their roles as professionals involved in the institution of the market. The result is the core of a theoretically defensible and managerially motivating and deployable ethic. |