This paper contributes to understandings of the production of normativity, i.e. the ways in which actors come to see rules as binding, in the context of corporate reporting regimes. Although the accounting literature recognises that a range of actors participate in the regulatory process, it continues to embrace dichotomous explanations of regulatory success based in the distinction between law and non-law, with law emanating from a binding system of rules, codified through state legislation and enforced by a coercive Westphalian state. Following this understanding there are calls for further regulation of reporting regimes in the literature. This paper demonstrates how a constructivist perspective can provide new insights to existing debates over regulation. More specifically, this theoretical perspective is applied to explore the production of normativity in two reporting regimes addressing environmental issues. One (the Spanish case study) was characterised by formal law enacted by the state which nonetheless lacked normativity. The other (the UK case study) was characterised by informal law induced by non-governmental organisations which appeared to acquire normativity. The problematisation of regulatory authority and legality offered by regime theory, constructivism and understandings of the processes by which norm cascades are generated reveals that, the internal legitimacy of the law is crucial in the construction of normativity and that while this was found in the UK case study, it was lacking in the Spanish case. These findings provide a more subtle set of considerations for understanding the role of regulation in reporting.