Recent advances in data collection and sharing techniques, typically associated with the popularised term ‘Big Data’, have led to increased calls for publicly funded arts organisations in the UK to embed data sharing practices into their operations. However, it is not yet clear what such practices mean for these organisations, specifically in relation to organisational legitimacy. Informed by in-depth, semi-structured, interviews with chief executives and other key informants from Arts Council funded, National Portfolio Organisations (NPOs), this developmental paper applies Giddens’ structuration theory as an analytical lens to identify whether and how the perceived legitimacy of NPOs are challenged by the data sharing policy mandate. This paper presents the early findings of the first author’s ongoing Ph.D research into the wider implications of data sharing policy and decision-making in publicly funded arts organisations.