This article is the result of our inquiry into two proximate fields in which issues of law, custom and markets arise in sociolegal scholarship and praxis: the mid-20th century jurisprudence of the legal realist Karl Llewellyn and the contemporary debates surrounding efforts by tribal governments in the U.S. to issue tax-exempt bonds. Both are sites for efforts by legal scholars and practitioners to grapple with the convergence of social categories that, until very recently, are normally held apart – Native Americans, law, and commerce. We first explore Llewellyn’s efforts at drafting the Uniform Commercial Code, and the extent to which in this and his The Cheyenne Way (written at virtually the same time), he drew considerable influence from the American pragmatist philosophical tradition. In so doing, we find that his jurisprudence and lawmaking (often maligned for its circular reasoning) can be better understood as an effort to announce a philosophy of law and enact commercial legislation that was more a method for doing legal analysis and taking legal action than it was an expression of legal principles. Once understood in this way, we suggest it offers a fresh way of accounting for the performative force of law that can move sociolegal research beyond certain constructivist impasses. We then offer how such an approach can be brought to bear on the unfolding relationships among custom, law and commerce in the back and forth between scholars, law-makers, and tribal leaders around tribal tax-exempt bonds and their regulation.