In this article, we examine how the sovereign state of Australia used accounting to assert its monopoly of sovereignty by suppressing the micronation of the Principality of Hutt River. With an increasing trend toward postnationalism, the status quo of sovereign states as sole providers of citizenship has been challenged by micronations. The Principality of Hutt River adopted the formal trappings of a sovereign state to uphold its independence from its host state, Australia. However, Australia responded through boundary work. Accounting was mobilised to deliver the coup de grâce to the principality by constraining its financial resources through a legal battle over tax collection. The Principality of Hutt River's formal trappings of a sovereign state and Australia's reaction through boundary work in dismissing any potential legitimacy for the micronation towards sovereignty illuminate the notions of the advent and operation of micronations in competition with sovereign states and the roles of accounting in the advance of a post-national zeitgeist.