Does the combined assurance model affect tax avoidance? The case of South African companies

Purpose This paper aims to investigate the impact of combined assurance on tax avoidance in South Africa. Design/methodology/approach This study is founded on a sample of 76 South African firms listed on the Johannesburg Stock Exchange over the 2014–2022 period. The authors used the feasible generalized least squares regression estimation technique to test the hypothesis. To address endogeneity issues, this study conducted a difference-in-differences (DID) analysis based on propensity score matching. Findings The results reveal that combined assurance negatively impacts tax avoidance. Implementing combined assurance, as an integrated risk management approach, significantly minimizes tax risk. The DID analysis provides well-founded evidence attributing the decline in tax avoidance levels to the availability of combined assurance. The inferences are robust to using alternative measures of tax avoidance, testing combined assurance impact across various tax avoidance levels and controlling for the COVID-19 effect. Practical implications This study presents valuable insights for firms, managers and policymakers. The findings encourage companies to bolster their risk management practices, opting for combined assurance over a sole risk monitoring mechanism. This approach enables the company to ensure better compliance with tax regulations, thereby enhancing overall efficiency. Besides, the disciplining effect of combined assurance motivates managers to make informed decisions, avoid tax avoidance strategies and safeguard corporate reputation. Moreover, this research calls upon policymakers to promote effective global regulatory frameworks for combined assurance practices. Originality/value The research brings original insights by exploring the influence of combined assurance on tax avoidance. This addresses a gap in the current literature that has predominantly focused on the relationship between tax avoidance and individual lines of defense.