Ethan J. Leib, David L. Ponet, and Michael Serota have
posted “Mapping Public Fiduciary Relationships” on SSRN.  Here is the abstract:

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.