Board ethnic diversity and the value relevance of antibribery and corruption disclosure

Antibribery and corruption disclosure (ABCD) has traditionally been conceptualised as a compliance-oriented reporting practice. However, whether and under what conditions such disclosure contributes to strategic value creation remains insufficiently understood. This study reconceptualises ABCD as a governance capability whose effectiveness depends on board-level structures, particularly board ethnic diversity (BED). Drawing on legitimacy, stakeholder and agency theories, we develop a configurational perspective in which disclosure effectiveness is contingent on governance capacity rather than on disclosure alone. Using a balanced panel of FTSE 100 firms from 2008 to 2022, we employ panel quantile regression (PQR) and a two-stage panel quantile (2SPQR) approach to capture distributional heterogeneity and address endogeneity. The findings reveal that both the quality and quantity of ABCD are positively associated with financial performance and ESG outcomes, but these effects vary across firms and are significantly strengthened by board ethnic diversity. The results suggest that ethical transparency becomes strategically valuable when supported by diverse and capable governance structures. This study contributes by advancing a contingent view of ethical disclosure, integrating governance and diversity mechanisms and offering methodological insights into heterogeneous sustainability-performance relationships. The findings have important implications for corporate strategy, regulatory design and societal efforts to strengthen ethical business conduct.