ABSTRACT Nordic countries are considered international leaders in producing combinable data on their citizens’ encounters with public institutions, as well as the digitalisation of public services. Public-sector professionals increasingly collaborate with private IT companies in developing data analytics products for cost saving and cost-efficiency. This article presents the results of a two-year ethnographic study of a collaboration between the Knowledge Team of a public-sector organisation and a private-sector IT company for developing and maintaining a data management system in one Finnish regional healthcare and social service organisation. The data management system is defined as a data analytics product that provides management with information about clinical and financial aspects of organisation management. We combine perspectives of science and technology studies and the sociology of professions to situate our research on the data management system as a boundary object within the broader context of professional work. Via our theoretical framework, we examine the negotiation process through which the data management system becomes a boundary object in practice. This process includes not only the accommodation of diverse epistemic cultures but also organisational and professional hierarchies that empower some experts to shape the data management system towards their visions and interests. This article applies the ‘boundary object’ concept to elucidate structural power differentials in public–private partnerships and multi-professional collaborations.