Purpose – The purpose of this paper is to document organizations' self descriptions of why they initiated sustainable development (SD) reporting and explore these explanations using an institutional theory framework. Design/methodology/approach – Constructs organizational narratives from semi-structured in-depth interviews with reporting champions who participated in an SD reporting workshop series. The narratives are analysed using institutional theory to explore how regulatory, normative and cognitive institutions combine with organizational dynamics to influence SD reporting activity. Findings – For these particular organizations, choosing to engage in reporting appears not to be a rational choice. Rather reporting is initiated because it has come to be an accepted part of pursuing a differentiation strategy, it offers some contribution to existing business challenges, and organizations value the rewards it offers. This rationale constitutes a cognitive mechanism within institutional theory. Originality/value – The paper provides useful information on initiating sustainable development reporting based on organizations' self descriptions.