Do audit committees enhance the credibility and assurance of ESG disclosures? evidence from listed firms in Sub-Saharan Africa

This study examines whether audit committee (AC) characteristics enhance the credibility and external assurance of environmental, social, and governance (ESG) disclosures in Sub-Saharan Africa (SSA). Using 1,800 firm-year observations from 200 non-financial listed firms in Ghana, Nigeria, Kenya, and South Africa over 2015–2024, we estimate two-step system GMM with Windmeijer-corrected standard errors, supplemented by pooled OLS, fixed-effects, and moderated-mediation specifications adapted to the dynamic-panel setting. AC independence, sustainability-oriented expertise, size, and meeting frequency are each positively associated with ESG disclosure credibility, and these characteristics indirectly raise the likelihood and scope of third-party ESG assurance. A one-standard-deviation increase in AC sustainability expertise is associated with a 0.094 increase in the ESG disclosure credibility index, equivalent to 23.8% of a standard deviation and 8.1% of the sample mean of the dependent variable, following the scaling convention recommended by Mitton (2024) and implemented in recent work by Shakri, Chung, and Ryu (2025). The indirect effect of AC characteristics on ESG assurance through disclosure credibility is conditional on firm size and regulatory regime, with stronger effects in larger firms and under the mandatory JSE integrated-reporting regime. Theoretically, the evidence shows that agency theory’s monitoring logic and stewardship theory’s trust-and-collaboration logic operate as complementary rather than substitute mechanisms: monitoring secures a disclosure-credibility floor where institutions are weak, while stewardship-oriented governance produces the beyond-compliance assurance ceiling. Coercive isomorphism (Scott, 2014) plausibly moderates the effect, with the AC-credibility link strongest where JSE listing rules, the Nigerian FRC sustainability roadmap, ICPAK’s Kenya roadmap, and Ghana’s ICAG IFRS S1/S2 timeline create enforceable sanctions. Ghana and Nigeria should move beyond weakly enforced “mandatory-in-principle” guidance toward ISSB-aligned phased mandates with delisting and penalty enforcement, and should require at least one AC member with recognised sustainability credentials given that fewer than 5% of SSA directors currently hold them. South Africa should accelerate CIPC’s mandatory sustainability reporting consultation and ISSA 5000 implementation to maintain its regional governance leadership.