The ‘threshold of materiality’ introduced by the High Court of Australia in Hossain v Minister for Immigration and Border Protection, and confirmed in subsequent cases, is a new presumption of statutory interpretation which universally qualifies the existing implied limitations on executive decision-making power. This article contends that the High Court did not adequately justify the presumption’s creation. It surveys several prior decisions to demonstrate the presumption’s doctrinal precariousness; criticises its lack of justification by reference to principles of statutory interpretation; and compares the Court’s creation of the presumption to other cases which, it is argued, have more persuasively justified the evolution of interpretative presumptions. Finally, the article discusses issues of pragmatism, the presumption’s reversal of the onus of proof, and the problematic residual discretion to refuse relief.