Abstract: This essay revisits the economic theory of fiduciary law. Nearly two decades have
passed since the publication of the seminal economic analyses of fiduciary law by Cooter and
Freedman (1991), and by Easterbrook and Fischel (1993), which together have come to underpin
the prevailing economic, contractarian model of fiduciary law. The economic theory of agency
that motivates those papers has come to permeate the literature on law and legal institutions
generally. The law-and-economics movement has matured further, developing new tools and
refining its understanding of previously applied concepts. The purpose of this essay is to restate
the economic theory of fiduciary law in an updated and accessible synthesis.