Can norms regulating business impact on society may be developed through public-private regulation? When enforcement institutions are weak, a rule’s effectiveness may depend on ‘compliance pull’ that may be enhanced by legitimacy. Looking at United Nations and EU cases of co-regulation of CSR, this work explores conditions for effectiveness and legitimacy for both process and output.

A pragmatic combination of legal and discourse theory and theory on legitimate law-making is adopted to analyse the construction of CSR normativity and discuss prospects. The analysis is based on four cases: the UN Global Compact; the development of the UN ’Protect, Respect and Remedy’ Framework on Business and Human Rights (‘the Ruggie Framework’); the EU Multistakeholder Forum on CSR; and the EU's CSR Alliance. All are approached as reflexive law and analysed as to strategies and results for norms on CSR and business impact on human rights. Reflexive law theory’s gap as to handling power disparities between participants is found to call for proceduralisation to equalize participation. This may enhance legitimacy for the purpose of process and output effectiveness and a compliance pull.

The thesis offers new insight through its combination of reflexive law and discourse theory to frame the analysis, exploration of negotiation strategies on CSR normativity, and recommendations of strategy, proceduralisation and processes for broad stakeholder participation (including through IT) for developing norms in the sustainability field.