The contemporary data economy is characterized by unprecedented opportunities for value creation alongside significant inequalities in the distribution of that value. Existing data governance frameworks, largely founded on the understanding of data as information and centred on privacy protection, have proven inadequate in addressing power asymmetries between data subjects, data holders, and data users. Although data cooperatives emerged as a promising institutional mechanism to democratize data governance and empower vulnerable stakeholders, they continue to face substantial legal, technological, and economic challenges. Their sector-specific orientation and limited conceptualization of data as a common informational resource constrain their scalability, interoperability, and capacity to realize the broader socio-economic potential of data. This study argues that these limitations stem from a deeper ontological issue: the prevailing understanding of data itself. By drawing on the theory of documentality, it proposes a reconceptualization of data as a social object or documedial resource whose value is jointly constituted through the interactions of multiple stakeholders. Such an understanding provides a stronger normative and theoretical foundation for cooperative governance. Documedial cooperativism recognizes both the informative and performative dimensions of data and consequently places social sustainability, fair value redistribution, and inclusive participation at the centre of data governance. By establishing a common conceptual framework across sectors and jurisdictions, documedial cooperativism offers greater potential for interoperability, scalability, and equitable economic participation. It reconciles the economic and social value of data, legitimizes broader collaborative uses of datasets, and provides a basis for fair remuneration of all contributors. Ultimately, the documedial approach represents a significant advancement in cooperative data governance, offering a more just, sustainable, and socially responsive framework for governing data in the digital age.