Abstract: In this paper, the authors conceptualize Open Data ecosystems byanalysing the major stakeholders in the UK. The conceptualization is basedon a review of popular Open Data definitions and business ecosystemtheories, which are applied to qualitative empirical data. The work isinformed by a combination of discourse analysis and a content analysis ofin-depth interviews, undertaken during the summer of 2013. Drawing on theUK as a best practice example, the authors examine a set of structuralbusiness ecosystem properties: circular flow of resources, sustainability,demand that encourages supply, and dependence developing between suppliers,intermediaries, and users. The authors identify that gaps and shortcomingsremain. Most prominently, demand is not yet fully encouraging supply andactors have yet to experience fully mutual interdependence.Keywords: Open Data, Ecosystem, Open Government Data, Case Study, UnitedKingdom