The first part of the thesis provides an analysis of previous studies on corporations as political actors in International Relations and International Political Economy. The aim of the theoretical research is to build a conceptual clarification with regard to the concept of global governance, power and authority focused on the transformation of transnational regulation in global governance and to enhance our understanding of business political power. The current research on the structure and processes of global governance highlights five empirical trends: First, the growth of the scale and the scope of non-state actors; second, the emergence of new governance systems that connect different constituencies, such as public and private actors; third, the growing legalisation surrounding environmental and social transnational politics; fourth, the segmentation of rule-making into different functional clusters and among multiple authorities; and, fifth, the emergence of new mechanisms at the global level, often in the form of novel institutional arrangements and actor coalitions.This part also focuses on the revision of the concepts that allow us to analyse the political role of businesses in the global political economy. The research attempts to understand the emergence of CSR beyond international public law in order to advance on knowledge regarding participation by private authorities in global governance. To understand the structure of CSR, the study focuses on the different range of critical approaches used to understand the influence of neoliberalism in the development of the new world order and the emergence of CSR. The second part focuses on global governance theoretical approaches and the emergence of new regulating transnational arrangements that have achieved effective solutions, transcending national boundaries and institutionalising the behaviour of private actors around a set of consciously devised and relatively specific global rules. From an institutional point of view, the emerging private regulating arrangements highlight the increasing density of rule-based interactions that have gradually given rise to an organisational field of transnational rule-making in global governance. The analyses adopt a matrix to classify the new typology of transnational regulation arrangements in which private authorities participate. The research focuses the study on the emergence of these new arrangements promoted by private authorities in dialogue and cooperation with global civil society organizations and other constellations of actors. The research also analyses the emergence of CSR within the framework of the global political economy. The study of CSR shows how it is based on the development of business self-regulation and the emergence of a new global public domain where NGOs and other networks within global civil society engage with the corporate sector to expand the web of corporate accountability, sustainability, labour and human rights initiatives. From this point of view, the critical international political economy approach lets us understand neoliberalism's influence and the role of business elites in CSR.Finally, the third part centers on the empirical analysis of CSR's institutionalization, taking into account the mechanisms that business elites promote to develop and implement CSR, especially private self-regulation and multistakeholder regulation. The empirical research analyses the role of neoliberal structuralist business elites in institutionalizing CSR though the creation of specific CSR and sustainability business associations. The empirical research creates a map of different business associations to promote CSR. The last part of the thesis provides a case study to analyse the emergence of CSR multistakeholder initiatives. The analysis of Global Reporting Initiative's institutionalisation focuses on the study of the role business leaders have on the GRI Board of Directors. It attempts to develop an empirical understanding of the role they play in decision-making and implementation processes for new forms of multistakeholder regulation. / The first part of the thesis provides an analysis of previous studies on corporations as political actors in International Relations and International Political Economy. The aim of the theoretical research is to build a conceptual clarification with regard to the concept of global governance, power and authority focused on the transformation of transnational regulation in global governance and to enhance our understanding of business political power. The current research on the structure and processes of global governance highlights five empirical trends: First, the growth of the scale and the scope of non-state actors; second, the emergence of new governance systems that connect different constituencies, such as public and private actors; third, the growing legalisation surrounding environmental and social transnational politics; fourth, the segmentation of rule-making into different functional clusters and among multiple authorities; and, fifth, the emergence of new mechanisms at the global level, often in the form of novel institutional arrangements and actor coalitions.This part also focuses on the revision of the concepts that allow us to analyse the political role of businesses in the global political economy. The research attempts to understand the emergence of CSR beyond international public law in order to advance on knowledge regarding participation by private authorities in global governance. To understand the structure of CSR, the study focuses on the different range of critical approaches used to understand the influence of neoliberalism in the development of the new world order and the emergence of CSR. The second part focuses on global governance theoretical approaches and the emergence of new regulating transnational arrangements that have achieved effective solutions, transcending national boundaries and institutionalising the behaviour of private actors around a set of consciously devised and relatively specific global rules. From an institutional point of view, the emerging private regulating arrangements highlight the increasing density of rule-based interactions that have gradually given rise to an organisational field of transnational rule-making in global governance. The analyses adopt a matrix to classify the new typology of transnational regulation arrangements in which private authorities participate. The research focuses the study on the emergence of these new arrangements promoted by private authorities in dialogue and cooperation with global civil society organizations and other constellations of actors. The research also analyses the emergence of CSR within the framework of the global political economy. The study of CSR shows how it is based on the development of business self-regulation and the emergence of a new global public domain where NGOs and other networks within global civil society engage with the corporate sector to expand the web of corporate accountability, sustainability, labour and human rights initiatives. From this point of view, the critical international political economy approach lets us understand neoliberalism's influence and the role of business elites in CSR. Finally, the third part centers on the empirical analysis of CSR's institutionalization, taking into account the mechanisms that business elites promote to develop and implement CSR, especially private self-regulation and multistakeholder regulation. The empirical research analyses the role of neoliberal structuralist business elites in institutionalizing CSR though the creation of specific CSR and sustainability business associations. The empirical research creates a map of different business associations to promote CSR. The last part of the thesis provides a case study to analyse the emergence of CSR multistakeholder initiatives. The analysis of Global Reporting Initiative's institutionalisation focuses on the study of the role business leaders have on the GRI Board of Directors. It attempts to develop an empirical understanding of the role they play in decision-making and implementation processes for new forms of multistakeholder regulation.