Fiduciary political theorists have neglected to explore sufficiently the difficulty of mapping fiduciary-beneficiary relationships in the public sphere. This oversight is quite surprising given that the proper mapping of fiduciary-beneficiary relationships in the private sphere is one of the most longstanding and strongly contested debates within corporate law. After decades of case law and scholarship directed towards the question of to whom do a corporation’s directors or managers serve as fiduciaries, private law theorists remain deeply divided. This debate within private law should be of perennial interest to public fiduciary theorists because the cartography of public fiduciary relationships is essential to operationalizing the project. After all, it is only through identifying the relevant fiduciary and beneficiary that one is able to determine the precise contours of the fiduciary framework’s ethical architecture. As such, loose mapping of fiduciary-beneficiary relationships in the public sphere precludes a clear understanding of whose interests are pertinent to the public fiduciary’s representation, and what the public fiduciary is to do when beneficiaries’ interests collide. The purpose of this chapter, then, is to explore the central debate in corporate law about fiduciary-beneficiary relationships to help translate fiduciary principles into public law configurations.