Core Capabilities of Data Trustees for Sovereign Data Sharing

Data sharing between organizations is a growing driver of value creation but demands trusted intermediaries. This study clarifies the role of data trustees, a neutral third party in data spaces, through a structured literature review and five expert interviews. We identify five core capabilities: (1) organizational independence and neutrality, to build trust; (2) coordination and enforcement of usage rights, enabling interoperability for a collaborative ecosystem; (3) fiduciary data custody and management, with optional services (e.g. data analytics, consulting, compensation, or anonymization and pseudonymization) regarding domain needs; (4) data offering and discovery via catalogs, marketplaces, or platforms; and (5) controlled transmission and orchestration using privacy-enhancing techniques (data sovereignty). We show how these capabilities can be operationalized to enable sovereign, interoperable, and privacy-preserving data sharing without creating new data monopolies, allowing multiple specialized trustees to coexist. The paper contributes a clear capability model and actionable design guidance for implementing data trustees in centralized and federated data spaces, providing a foundation for organizations to access and contribute high-quality data for data products, advanced analytics, and AI.