Bona Vacantia and the Administration of Ownerless Property: A Global Review of Theory and Practice

The doctrine of bona vacantia, referring to property without an apparent owner, remains an underexamined aspect of property law with significant theoretical and practical implications. Despite its long-standing presence, the administration continues to face challenges in terms of efficiency, accountability, inclusivity, and social utility. In many jurisdictions, fragmented frameworks have left unclaimed estates, abandoned land, and vacant assets underutilised or mismanaged. This study conducts a global comparative review, drawing on common law and civil law traditions with reference to selected countries. It integrates statutory interpretation, doctrinal commentary, and secondary literature to examine how states conceptualise and administer unclaimed property. Beyond description, the paper critically evaluates the effectiveness of different approaches, highlighting trade-offs between fiscal custodianship, social utility, and institutional capacity. The analysis considers the social and economic impacts of bona vacantia policies, including São Paulo’s vacancy penalties that promote housing access, Japan’s land banks reintegrating abandoned housing into local markets, and Portugal’s limited municipal garden schemes. It also addresses conflicts between customary, religious, and statutory frameworks, particularly in pluralistic jurisdictions, and discusses strategies for reconciliation through legislative harmonisation, judicial interpretation, and administrative coordination. The findings indicate that effective governance of bona vacantia necessitates more than state custodianship; it must strike a balance between legal certainty, distributive justice, and long-term sustainability. Reconceptualising ownerless property as a resource for social development and sustainable land management offers a pathway for transforming a dormant legal doctrine into a constructive instrument of public policy.