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

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

Siti Khadijah binti Abdullah Sanek^*, Mohd Zulhelmey bin Abdullah Abd Halim, Nur Irinah binti Mohamad Sirat, Nurul Mazrah binti Manshor, Salmah binti Roslim, Syatirah binti Abu Bakar

Department of Law, University Technology MARA Cawangan Kedah, 08400 Merbok, Kedah, Malaysia

*Corresponding author

DOI: https://dx.doi.org/10.47772/IJRISS.2025.909000495

Received: 09 September 2025; Accepted: 14 September 2025; Published: 15 October 2025

ABSTRACT

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.

Keywords — Bona Vacantia, Ownerless Property, State Custodianship, Sustainability, Property Governance

INTRODUCTION  

The concept of bona vacantia, literally meaning “ownerless goods,” occupies a significant place in property law, reflecting how states and societies deal with assets that lack identifiable heirs or claimants. In most jurisdictions, such property devolves to the state by operation of law, yet the administration of bona vacantia is far from uniform. Its regulation is shaped by diverse legal traditions, socio-economic priorities, and cultural values, making it a contested and evolving area of research (López & Gamboa, 2020; Besley, 1995; Ostrom, 1990). The question of who ultimately benefits from ownerless or heirless estates raises broader debates about distributive justice, social welfare, and the public function of property (Campbell, 1996; Burdick, Garmany, & Gurr, 2024).

While the doctrine has a clear historical basis, its practical application today extends well beyond inheritance disputes. In certain contexts, such as Brazil, constitutional directives on the social function of property permit municipalities to impose sanctions on landowners who fail to use their vacant land to promote collective welfare (Friendly, 2025; Carneiro & Dias da Silva, 2020). Elsewhere, particularly in countries such as Japan and Portugal, the issue intersects with urban planning, sustainability, and demographic change, as governments strive to manage growing inventories of abandoned land and housing (Yin & Shimizu, 2025; Ribeiro, Carvalho, & Madureira, 2020; Baba & Hino, 2019). At the same time, the lack of clarity in legal definitions, such as in Colombia, where high court pronouncements remain fragmented, creates uncertainty and undermines legal security (López & Gamboa, 2020; Kharitonashvili, 2024). This inconsistency points to a persistent challenge: the gap between the theoretical underpinnings of bona vacantia and the practical realities of its administration (Hirokawa & Gonzalez, 2010; Shaw, 2010).

 Research in this area has contributed valuable insights into this area, examining themes such as compulsory acquisition for public benefit (Ferlan et. al., 2009), the role of customary tenure in balancing tradition with market-driven reforms (Chand, 2017), and the socio-economic disparities arising from redevelopment programs and urban vacancy (Kim, 2016; Lee & Newman, 2019; O’Callaghan, 2024). Research has also highlighted the management of vacant properties through state intervention (Henderson, 2015), land banking (Yin & Shimizu, 2025), and community-based models of common property (Ostrom, 1990; Perilla Granados, 2025). However, these studies tend to be fragmented, often focusing on single jurisdictions or policy instruments, without providing a comprehensive synthesis of global practices. As a result, there remains a limited understanding of how different legal frameworks interact with broader socio-economic and cultural factors in shaping the governance of ownerless property (Ho, 2024; Takamura, 2021).

This review addresses that gap by systematically analysing the administration of bona vacantia across diverse jurisdictions, constructing a conceptual map that links legal doctrines, policy mechanisms, and socio-economic outcomes. By drawing upon a wide range of studies, including those on property management competencies (Ab Wahab et al., 2020; Khan & Hui, 2010), urban vacancy (Chen, 2025; Verdú Martínez, 2018), and the comparative role of vacant goods in Latin America (López & Gamboa, 2020), the paper identifies emerging themes in the field. These include the integration of property law with urban planning, the balancing of customary rights with development imperatives, and the implications of property redistribution for equity and social justice (Fearon, 2003; Guseinova, Zayni, & Afanasyeva, 2016). Furthermore, the analysis incorporates the perspectives of topic experts, highlighting how theoretical frameworks translate or fail to translate into effective governance (Falagas et al., 2008).

The contribution of this paper is two-fold. First, it synthesises fragmented literature into a coherent comparative framework, providing a comprehensive account of global approaches to bona vacantia and ownerless property. Second, it identifies critical gaps and future research routes, particularly in relation to equitable governance, sustainability, and the interplay between law and socio-economic policy. In doing so, it advances scholarly debates while offering practical insights for policymakers tasked with managing heirless and unclaimed property.

The paper is structured as follows. This paper begins by tracing the historical and conceptual foundations of bona vacantia and ownerless property, before examining comparative legal frameworks in jurisdictions such as the United Kingdom, Malaysia, Brazil, Japan, and Portugal. It then discusses the social, economic, and property management implications of these frameworks, with attention to urban development and community welfare. The analysis highlights key findings and reflects on theoretical and practical dimensions of governing unclaimed property. The paper concludes with a summary of contributions, limitations, and directions for future research.

METHODOLOGY

This study employs a systematic review approach, utilising Scopus AI as the primary research tool to identify, analyse, and synthesise relevant literature on the administration of bona vacantia and ownerless property across various jurisdictions. Scopus was selected given its status as one of the most comprehensive bibliographic databases for peer-reviewed publications, offering extensive coverage across law, social sciences, and interdisciplinary studies (Falagas et al., 2008). The review was conducted on 19th August 2025, ensuring that the most up-to-date and relevant scholarship was incorporated into the analysis.

The search strategy was designed to capture both theoretical and practical dimensions of bona vacantia. To achieve this, a structured search string was developed as follows:

(“bona vacantia” OR “ownerless property” OR “unclaimed property” OR “abandoned property”) AND (“administration” OR “management” OR “governance” OR “oversight”) AND (“legal framework” OR “law” OR “regulation” OR “policy”) AND (“property rights” OR “ownership” OR “title” OR “claim”) AND (“distribution” OR “allocation” OR “disposition” OR “transfer”)

The Scopus AI interface provided multiple layers of outputs, namely Summary, Expanded Summary and Concept Map, each of which was systematically analysed.

The Summary presented an overview of the existing scholarship, identifying recurring legal, socio-economic, and cultural dimensions of bona vacantia. The Expanded Summary offered more granular insights into jurisdictional variations, highlighting, for example, Brazil’s approach to the social function of property, Japan’s land bank initiatives, and Colombia’s definitional ambiguities (López & Gamboa, 2020; Friendly, 2025; Yin & Shimizu, 2025).

The Concept Map generated by Scopus AI was used to visually connect key domains of inquiry, including (i) legal framework underpinning bona vacantia, (ii) property management, (iii) social implications of ownerless property, and (iv) international practices. This conceptual mapping guided the synthesis by ensuring that the review captured both doctrinal analyses and practical applications, thereby aligning with the study’s aim of linking legal frameworks with socio-economic outcomes.

Taken together, this methodological framework supports the study’s aim of systematically analysing global practices in the administration of bona vacantia, constructing a conceptual map of interrelated legal and policy domains, and identifying emerging challenges and opportunities for equitable governance. By leveraging Scopus AI’s integrated tools, this review not only synthesises existing literature but also advances a forward-looking agenda for research and practice in property law.

Figure 1. Scopus AI Analysis of Bona Vacantia

Figure 1 illustrates the methodological framework of this study, highlighting the layered outputs generated by Scopus AI during the literature search conducted on 19 August 2025. At the outermost layer, the Summary provides a concise overview of existing scholarship, serving as the entry point into the research field. Building on this, the Expanded Summary offers deeper jurisdiction-specific insights, capturing comparative variations in the administration of bona vacantia and ownerless property. The Concept Map represents the visual interconnections between legal frameworks, governance mechanisms, socio-economic implications, and policy innovations, ensuring a structured synthesis of knowledge. Collectively, these outputs demonstrate how Scopus AI facilitates a multi-dimensional review process, enabling a systematic mapping of theory and practice in the administration of bona vacantia.

RESULTS AND DISCUSSION

The findings of this review are presented in four interrelated layers derived from the Scopus AI analysis conducted on 19 August 2025: (i) Summary and Expanded Summary, and (ii) Concept Map. Together, these layers provide a comprehensive understanding of how bona vacantia and the administration of ownerless property are theorised, legislated, and practised across jurisdictions.

1) Summary and Expanded Summary: The global review of bona vacantia and the administration of ownerless property reveals significant diversity in legal frameworks, practical mechanisms, and socio-economic impacts across jurisdictions. While the underlying principle of transferring unclaimed or ownerless assets to the state is universal, the modes of implementation and implications for property law, urban governance, and social equity vary widely. This demonstrates that bona vacantia is not a static doctrine, but a dynamic institution shaped by cultural, economic, and political contexts.

In terms of legal frameworks, countries differ in their recognition and definition of vacant property. In Colombia, the absence of a clear statutory definition of vacant goods has resulted in fragmented judicial interpretations, thereby undermining legal certainty and due process (López & Gamboa, 2020). By contrast, Brazil recognises the category of terra devoluta but presumes private ownership under the 2002 Civil Code, allowing for prescription-based acquisition, thus excluding such land from the scope of bona vacantia (López & Gamboa, 2020). These examples demonstrate how legal ambiguity, or conversely, legal presumption, significantly affects the administration of property rights and the state’s ability to manage ownerless assets. Critically, Brazil’s approach illustrates a socially progressive orientation but also introduces risks of inconsistent enforcement, while Colombia’s fragmented framework prioritises private rights yet leaves gaps in public interest protection. Hence, the effectiveness depends not just on the presence of laws, but on their clarity, enforceability, and responsiveness to social needs.

The concept of the social function of property further enriches the debate on bona vacantia, particularly in urban contexts. In São Paulo, municipalities may impose penalties on property owners who leave land unused, aligning property rights with broader social goals of reducing vacancy and promoting housing accessibility (Friendly, 2025). This reflects an innovative approach where bona vacantia principles intersect with urban planning policies, shifting the administration of property from passive state acquisition to proactive measures that serve collective needs. The measure has demonstrated tangible social benefits by reducing idle landholdings and encouraging reinvestment in urban housing. However, the success of such penalties depends on institutional capacity to enforce them consistently, suggesting that innovation alone is insufficient without sustained governance support. Similarly, Japan has developed mechanisms such as Land Banks to manage its growing inventory of abandoned houses and land with unclear ownership, linking property administration to urban revitalisation and community development (Yin & Shimizu, 2025). These strategies have generated measurable benefits, including reintegration of vacant homes into the housing market, but critics note challenges of financing, bureaucratic delays, and demographic decline. By contrast, Portugal’s Municipal Master Plans (MMPs), though offering potential to convert vacant land into sustainable urban gardens, have yet to fully exploit this opportunity due to gaps in regulatory support (Ribeiro et al., 2020). This uneven record highlights that while innovative models can deliver social and economic dividends, their long-term effectiveness hinges on structural and institutional conditions.

Beyond statutory law, customary practices also influence the administration of ownerless property. Papua New Guinea offers a unique example where land reforms aimed to reconcile traditional collective ownership with modern economic demands by facilitating long-term leasing for private enterprises (Chand, 2017). This model highlights the potential for hybrid systems that respect cultural values while fostering economic development. At the same time, it demonstrates the difficulties of reconciling customary tenure with statutory regimes, as conflicts over land use and legitimacy persist. The broader lesson here is that hybrid frameworks can enhance inclusivity but must be accompanied by clear dispute resolution mechanisms to prevent overlapping claims from undermining certainty.

Despite innovative practices, challenges persist in achieving equitable outcomes in the management of ownerless or vacant properties. In New York City, the Brownfield Cleanup Program (BCP) has been criticised for disproportionately benefiting wealthier, predominantly White neighbourhoods, while offering limited support to marginalised communities (Porter, 2009). This underscores the socio-economic disparities that may arise when bona vacantia and related land management policies are implemented without careful attention to distributive justice. Similarly, Portugal’s municipal initiatives, while progressive in theory, reveal the limits of under-resourced frameworks. Collectively, these examples suggest that legal and policy interventions must be evaluated not only by their design but by their distributive consequences.

Finally, compulsory acquisition emerges as another dimension of bona vacantia practice, where states utilise their authority to secure land for public benefit. Slovenia’s experience demonstrates how legal mechanisms can balance individual property rights with collective needs, emphasising that the public interest may sometimes justify state intervention in property administration (Ferlan et al., 2009). Such cases highlight the tension between private rights and public good, a recurring theme in the global discourse on bona vacantia. Critically, the lesson here is that compulsory acquisition, when transparently implemented and adequately compensated, can function as a legitimate policy tool. However, without safeguards, it risks eroding trust and deepening inequalities.

Taken together, these findings indicate that while the theory of bona vacantia provides a foundational principle for state acquisition of ownerless property, its practice is far from uniform. Jurisdictions such as Brazil and Japan showcase innovative approaches that integrate property administration with urban planning and community development, while contexts like Colombia and New York expose the risks of legal ambiguity and inequitable policy outcomes. The evaluative evidence suggests that effectiveness depends on aligning legal certainty with distributive justice and institutional capacity. Overall, effective management of bona vacantia requires not only clear legal definitions but also frameworks that balance public interest, socio-economic equity, and cultural considerations.

2) Concept Map: Figure 2 presents the Scopus AI-generated concept map (as of 19 August 2025), which organises the core dimensions of research on bona vacantia and ownerless property. The visualisation highlights the interconnected dimensions of bona vacantia and ownerless property, highlighting how this phenomenon extends beyond legal doctrine into wider social, economic, and administrative contexts. At its core, bona vacantia interacts with four primary domains: international practices, social implications, property management, and legal frameworks, each of which generates multiple sub-themes.

From a global perspective, international practices reveal the roles of both public administration and the private sector in absorbing or reutilising ownerless assets, often reflecting jurisdictional differences in state involvement. The social implications cluster emphasises the community-level effects, such as the role of social housing initiatives and community organisations in mitigating urban decline linked to vacant property. Meanwhile, the property management strand covers practical challenges, including the use of land banks and the persistence of vacant land. Finally, the legal framework node anchors the discussion in law, connecting to the responsibilities of state registration agencies and broader questions of rights to real estate, and issues surrounding the encumbrance of ownership rights, which often hinder effective utilisation, underscoring the legal infrastructure necessary for resolving disputes over ownership and ensuring effective governance.

Collectively, this mapping highlights that the administration of bona vacantia is not a narrow technical exercise but a multi-layered process with economic, social, and institutional implications. It provides a thematic foundation for analysing how certain countries respond to the challenges of ownerless property while balancing revenue generation, social welfare, and sustainable urban management.

Figure 2. The Scopus AI-generated concept map

The Relationship between Bona Vacantia and Ownerless Property:

The doctrine of bona vacantia, derived from Roman law, refers to property that has no owner and thus reverts to the state or sovereign authority. In practice, the concept overlaps significantly with the treatment of vacant or heirless property in urban and property law. Globally, governments face increasing challenges in regulating vacant properties due to their adverse effects on urban landscapes, including declining property values, increased crime, and urban blight. Regulatory frameworks, particularly in developed cities, have been developed to mitigate these risks, reflecting the functional application of bona vacantia in modern property governance (Hirokawa & Gonzalez, 2010).

A key difficulty in implementing bona vacantia principles lies in legal uncertainty, particularly in defining vacant property and its ownership boundaries. In Colombia and Brazil, scholars highlight that ambiguous legal definitions create tensions between individual property rights and state intervention (López & Gamboa, 2020). These uncertainties hinder effective administration of ownerless property and raise broader questions about the legitimacy of state claims over property that appears abandoned but may still be subject to contested rights. This tension illustrates the doctrinal complexity of bona vacantia, as the state’s custodial role must be balanced with constitutional protections for private property.

Recent scholarship also emphasises the need to advance the theorisation of vacancy in urban research. Historically undertheorized, vacant land has recently become a focal point for urban geographers seeking to understand its socio-economic and legal implications (O’Callaghan, 2024). Bona vacantia provides a conceptual entry point for reconciling the legal treatment of ownerless property with broader urban processes, such as gentrification, housing shortages, and sustainable development. This theoretical resurgence aligns with global recognition that urban vacancy cannot be dismissed as a marginal issue but must be integrated into mainstream discussions of land management and urban planning.

The practice of regulating ownerless property is particularly evident in cities like São Paulo, where constitutional provisions empower municipalities to take punitive action against prolonged urban vacancy (Friendly, 2025). Such approaches demonstrate how bona vacantia is operationalised as a tool for social justice, ensuring that land left idle is redirected toward productive or socially beneficial uses. Similarly, methodological innovations, such as the classification scheme for vacant urban lands developed in Minneapolis, provide practical tools for identifying, categorising, and reusing vacant properties (Lee & Newman, 2019). These practices highlight a shift from passive acceptance of vacancy to active governance in line with the doctrine of bona vacantia.

Finally, from a property law perspective, the concept of vacant possession underscores the importance of ensuring that property, once transferred or inherited, is left unencumbered and in a usable state. Shaw (2010) argues that this principle is essential for protecting property markets and ensuring smooth transactions. When linked to bona vacantia, vacant possession demonstrates the continuity between private law principles and the broader public law administration of ownerless property. Taken together, these theoretical and practical insights reveal that bona vacantia serves as a crucial bridge between property law, urban governance, and socio-economic policy.

The Linkages between Bona Vacantia and Ownerless Property with International Practices:

The administration of bona vacantia and ownerless property has emerged as a critical concern across jurisdictions, reflecting the intersection of law, urban policy, and community welfare. At its core, bona vacantia represents the state’s claim over property that lacks a legal owner, but its practical administration varies widely in international contexts. For instance, in many urban environments, vacant properties are viewed not only as legal anomalies but also as triggers of urban decline, prompting municipalities to implement regulatory frameworks aimed at mitigating blight and stabilising property values (Hirokawa & Gonzalez, 2010). This demonstrates that while the principle of state acquisition remains central, international practices increasingly surround social and economic considerations in the management of ownerless assets.

From a theoretical standpoint, challenges also arise in the field of international law, where definitions of property remain fragmented. Ho (2024) observes that international property regulation lacks cohesion, resulting in gaps where vacant and ownerless assets are insufficiently addressed. This highlights the difficulty of transplanting domestic notions of bona vacantia into the global sphere, where sovereignty, jurisdiction, and recognition of property rights vary significantly. As a result, while states may adopt robust national frameworks, the absence of harmonised international principles leaves unresolved questions concerning cross-border property, inheritance disputes, and the treatment of foreign-owned abandoned assets.

Comparative studies illustrate the divergent legal approaches to vacant property within national contexts. López and Gamboa (2020) reveal how Colombia and Brazil adopt contrasting definitions and regulatory regimes, producing legal uncertainty and perpetuating inequitable access to land. Similarly, Friendly (2025) highlights the persistence of urban vacancy in São Paulo, framing it as a common property issue that demands innovative governance. These findings underscore that bona vacantia is not merely a matter of state enrichment but is deeply entangled with distributive justice, urban planning, and property rights. The comparative dimension suggests that legal uncertainty, unless resolved, risks undermining both social cohesion and economic development.

Country-specific initiatives further demonstrate the practical experimentation taking place in response to ownerless property. In Japan, the rise of vacant houses and land (akiya) has spurred both governmental and community-driven land bank models designed to reintegrate unused assets into the housing market and local economies (Yin & Shimizu, 2025). These approaches mark a shift away from passive state claims under bona vacantia toward proactive reallocation strategies that prioritise social utility and sustainable development. By leveraging institutional innovation, Japan illustrates how states can transform the challenges of ownerless property into opportunities for urban regeneration and local empowerment.

Finally, experiments in temporary use have also gained traction as part of international practice, reflecting a balance between legal certainty and flexible adaptation. Case studies from Bremen, Rome, and Budapest demonstrate how municipal governments collaborate with citizen initiatives to repurpose vacant properties on a temporary basis, creating space for cultural, social, and economic activities (Patti & Polyak, 2017). This model exemplifies how ownerless and vacant property management is evolving into a dynamic field that integrates law, policy, and civic participation. Taken together, the global review of theory and practice reveals that while the doctrine of bona vacantia retains its traditional legal meaning, its contemporary application is increasingly shaped by international practices that emphasise regeneration, inclusivity, and sustainable urban futures.

The Linkages between Bona Vacantia and Ownerless Property with Social Implications:

The administration of bona vacantia and ownerless property carries significant social implications that extend beyond legal and financial concerns. At its core, property that lacks a rightful heir or owner raises questions of social justice, urban inequality, and community well-being. When states assume ownership of such property, they are entrusted not only with managing economic value but also with addressing broader social needs, such as housing shortages, urban regeneration, and the equitable distribution of resources (Friendly, 2025). Thus, how societies regulate ownerless property reflects broader social priorities and governance philosophies.

A central social implication of bona vacantia is its connection to urban decline and neighbourhood blight. Vacant and abandoned properties often lead to depreciating land values, increased crime, and diminished quality of life for residents living nearby (Hirokawa & Gonzalez, 2010). Communities disproportionately affected by high concentrations of ownerless or vacant properties are often low-income or marginalised, exacerbating cycles of disadvantage. The state’s role in mitigating these effects, whether through land banking or social housing schemes, demonstrates how property administration is entangled with social equity.

At the same time, ownerless property also presents opportunities for community empowerment and innovation. In several jurisdictions, community organisations have mobilised to reclaim and repurpose vacant land for social uses, such as community gardens, cooperative housing, and cultural spaces (Patti & Polyak, 2017). These initiatives highlight how social actors can collaborate with local governments to transform neglected spaces into assets that foster inclusion, resilience, and sustainability. Such practices reflect a shift from viewing bona vacantia merely as a legal anomaly to recognising it as a catalyst for social regeneration.

Cross-national perspectives further reveal that social implications vary according to legal and cultural contexts. For example, in Japan, vacant houses, often termed akiya, pose challenges not only for urban management but also for demographic and social cohesion, as depopulation leads to weakened community ties (Yin & Shimizu, 2025). By contrast, in Latin America, unresolved questions about the social function of property contribute to tensions between individual ownership rights and collective access to land (López & Gamboa, 2020). These variations underline the importance of situating bona vacantia within broader debates on social justice, property rights, and state responsibilities.

Ultimately, the social implications of bona vacantia and ownerless property reflect the tension between exclusion and inclusion. On the one hand, neglected and vacant properties symbolise systemic failure, leaving vulnerable groups exposed to deteriorating environments. On the other hand, innovative governance frameworks and community participation can reimagine these properties as vehicles for social good, promoting affordable housing, sustainable urban development, and greater social cohesion (Ho, 2024). Therefore, the regulation of bona vacantia should not be confined to administrative or financial considerations but must also prioritise its profound social consequences.

The Linkages between Bona Vacantia and Ownerless Property with Property Management:

The management of bona vacantia and ownerless property represents a complex intersection between legal frameworks and property management practices. From an administrative standpoint, such properties require clear mechanisms for identification, valuation, and eventual transfer to ensure that they do not remain idle or become liabilities for communities. Property management, therefore, plays a pivotal role in transforming these legally ambiguous assets into usable and socially productive resources (Ho, 2024). Without effective management strategies, bona vacantia risks contributing to urban decline and resource inefficiency.

One key property management challenge lies in the maintenance and preservation of ownerless assets. Vacant land and abandoned buildings often deteriorate rapidly when not actively managed, leading to declining property values and increased costs of restoration (Hirokawa & Gonzalez, 2010). In this sense, property management functions not merely as a technical process of upkeep but as a preventive measure against broader socio-economic decline. Governments, acting as custodians of bona vacantia, must therefore adopt proactive approaches that include regular inspections, rehabilitation programs, and integration of these assets into urban development plans.

Another dimension of property management is the allocation and repurposing of ownerless properties to meet public needs. In many jurisdictions, bona vacantia is converted into land banks, which serve as strategic reserves for housing, infrastructure, or community facilities (Yin & Shimizu, 2025). By managing such properties through structured frameworks, governments and local authorities can directly address pressing urban issues, such as shortages of affordable housing or a lack of public spaces. This reallocation reflects the managerial function of ensuring that dormant assets are harnessed for the benefit of society.

At the same time, effective property management of bona vacantia requires collaboration with private and community actors. Public–private partnerships can mobilise resources for redevelopment, while community organisations can guide the adaptive reuse of properties to suit local needs (Patti & Polyak, 2017). These collaborative models highlight how property management is no longer confined to bureaucratic administration but involves multi-stakeholder engagement to ensure that ownerless properties are managed efficiently, sustainably, and inclusively.

Ultimately, the relationship between bona vacantia, ownerless property, and property management demonstrates that legal ownership is only the first step; the real challenge lies in administration. Property management ensures that assets transition from being legally ownerless to becoming socially and economically functional. This relationship underlines the importance of embedding property management principles within legislative frameworks on bona vacantia, so that idle assets are systematically preserved, repurposed, and reintegrated into urban systems (Friendly, 2025). As such, property management acts as the critical link that transforms dormant legal categories into practical tools for sustainable development.

The Linkages between Bona Vacantia and Ownerless Property with Legal Framework:

The doctrine of bona vacantia is a long-standing principle under common law, where property without an identifiable owner reverts to the state. Its core function is to ensure that property ownership never remains legally uncertain, thereby protecting social order and property rights. This framework highlights the dual purpose of property law: securing ownership while preventing economic inefficiencies that arise from abandoned or unclaimed assets (Ho, 2024). In practice, legal frameworks governing bona vacantia vary across jurisdictions, reflecting differences in how states conceptualise property rights, succession, and public interest.

Globally, the regulation of ownerless property often extends beyond the common law doctrine of bona vacantia to encompass statutory frameworks addressing vacant land and abandoned buildings. For example, in Portugal, legal frameworks have been developed to repurpose vacant land into urban gardens, reflecting how ownerless property can be redirected for sustainable purposes (Ribeiro, Carvalho, & Madureira, 2020). Similarly, in the United States, local governments exercise broad discretion in regulating vacant property, using municipal codes and zoning laws to combat urban blight and declining property values (Hirokawa & Gonzalez, 2010). These practices illustrate that while the doctrinal roots of bona vacantia lie in private law, modern frameworks emphasise broader social and environmental considerations.

In Latin America, however, the legal treatment of vacant property reveals challenges of legal uncertainty. Colombia, for instance, struggles with ambiguities in defining “vacant goods,” which has led to disputes over property rights, due process, and the role of the state in land redistribution (López & Gamboa, 2020). Brazil has similarly faced tensions between constitutional guarantees of private property and the state’s ability to claim or redistribute vacant lands for social purposes. These cases highlight the limitations of legal frameworks that fail to reconcile private ownership rights with public interest objectives, contrasting with the more settled doctrine of bona vacantia in common law systems.

Social movements also shape legal frameworks governing ownerless property. In Spain, the okupa (squatter) movement has prompted the development of a consolidated regulatory framework that balances constitutional property rights with the realities of housing shortages and the occupation of vacant private property (Perilla Granados, 2025). These movements demonstrate that the administration of ownerless property is not only a legal issue but also a socio-political one, where legal frameworks are pressured to evolve in response to urban inequality.

Taken together, the global review reveals that bona vacantia and the legal frameworks for ownerless property perform a stabilising role by preventing property from existing in a legal vacuum. However, contemporary practice shows a shift from mere state custodianship to more dynamic frameworks that incorporate social, economic, and environmental objectives. While common law jurisdictions rely on the established doctrine of bona vacantia, civil law and mixed systems experiment with statutory innovations and community-driven practices. This comparative perspective underscores that effective legal frameworks must balance three imperatives: protecting property rights, ensuring orderly administration, and promoting socially beneficial uses of ownerless property.

CONCLUSIONS

This study has explored the doctrine of bona vacantia and the administration of ownerless property, offering a global review of theory and practice across multiple jurisdictions. The key findings reveal that while the principle of state custodianship of ownerless assets is common, its application varies significantly depending on the legal, cultural, and economic context. In the United Kingdom, bona vacantia primarily functions as a fiscal mechanism benefiting the Crown; in Malaysia, a dual system of civil and Islamic law shapes the treatment of unclaimed estates; while in countries such as Brazil, Japan, and Portugal, vacant or abandoned properties are increasingly linked to broader issues of urban management, social housing, and community regeneration. This comparative analysis highlights that the administration of bona vacantia is not merely a technical legal matter but one deeply intertwined with property rights, social justice, and public policy.

From a theoretical perspective, the study underlines the need to re-examine bona vacantia through the lens of modern property theory, particularly in relation to the social function of property and the commons. Ownerless property, traditionally viewed as a passive legal anomaly, can instead be conceptualised as a resource that carries potential value for society. This shift challenges classical understandings of property as an individual right and emphasises its relational, distributive, and developmental dimensions.

Practically, the research shows that effective administration of bona vacantia requires not only clear statutory frameworks but also proactive governance strategies. Jurisdictions that integrate unclaimed property into housing policies, environmental sustainability, or local community initiatives demonstrate greater social returns compared to those treating such assets solely as revenue for the state. The comparative evidence suggests that a balanced approach combining state custodianship with social utility offers the most promising model.

Nevertheless, the study has several limitations. The reliance on secondary sources and doctrinal analysis means that the perspectives of stakeholders, such as local administrators, heirs, or affected communities, are not directly captured. Moreover, while the research draws on examples from multiple jurisdictions, it does not exhaustively cover all legal systems, and certain regions, particularly Africa and the Middle East, remain underexplored.

Future research should therefore expand the empirical scope by incorporating field studies, interviews, and case analyses to better understand the lived realities of bona vacantia administration. Comparative studies focusing on emerging economies and developing legal systems could further illuminate how unclaimed property intersects with issues such as poverty alleviation, land reform, and urbanisation. Additionally, interdisciplinary research bridging law, economics, and urban planning would help reconceptualise bona vacantia as not merely a residual doctrine but as a dynamic tool for sustainable development and equitable property management. Importantly, future inquiry should also explore mechanisms to reconcile customary, religious, and statutory legal frameworks, particularly in pluralistic systems such as Malaysia, where overlapping claims can undermine inclusivity and legal certainty. At the same time, greater attention should be given to assessing the long-term sustainability of innovative mechanisms, such as land banks in Japan or municipal interventions in Brazil and Portugal. While these initiatives illustrate the transformative potential of ownerless property, their success depends on adequate legal foundations, institutional capacity, and community acceptance. Embedding such innovations within coherent legal and policy frameworks will be essential if bona vacantia is to evolve into a sustainable instrument of equitable property governance.

ACKNOWLEDGMENT

The authors would like to express their sincere gratitude to the Kedah State Research Committee, UiTM Kedah Branch, for the generous funding provided under the Tabung Penyelidikan Am. This support was crucial in facilitating the research and ensuring the successful publication of this article.

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