Purpose: This paper examines the factors and determinants of sustainability reporting and assurance (SRA) worldwide.

Design/methodology/approach: We perform descriptive and regression analyses in determining the trends in quality and quantity of SRA and determinants of SRA using the Global Reporting Initiative database from 2005-2016.  

Findings: We find: (1) the quantity and quality of SRA have significantly increased worldwide in the past decade; (2) a positive association between the quality and quantity of SRA and sustainability disclosure, and the United Nations Sustainable Development Goals (SDGs); (3) sustainability reporting quantity and quality are significantly associated with legal, social, ethical and environmental factors.

Research limitations/implications:  We collect sustainability reporting and assurance quantity and quality from the GRI database and thus our results are affected by the data availability of the most recent years. Furthermore, the selected variables as proxies for the determinants of SRA are collected from the UN sustainability development goals that are evolving and are not all inclusive.

Practical implications: Our findings are relevant to current debates among global policymakers, regulators, standard-setters, the business community, and the accounting profession in improving the quantity and quality of SRA by standardizing reporting on ESG sustainability information.

Social implications: This paper untangles whether an increased quality and quantity of SRA is value relevant to investors by linking SRA factors to SRA determinants.

Originality/value: Our results provide insight to both factors and determinants of SRA, which shed light in identifying the nature and benefits of SRA in the highly controversial voluntary disclosure literature.