ESG performance and women’s presence on the board: do operating cash flow opacity and sustainability committees matter? Evidence from the UK FTSE 100

Purpose This study aims to examine how women on corporate boards affect environmental, social and governance (ESG) performance, focusing on the moderating role of operating cash flow (OCF) opacity and the mediating role of sustainability committees (SCs). Drawing on agency, stakeholder and signalling theories, it explores how leadership structure and financial transparency shape ESG performance in the UK. Design/methodology/approach This study uses panel data from FTSE 100 firms for the period 2014–2023. The analysis uses fixed-effects regressions and two-stage least squares estimations. Mediation effects were tested using Baron and Kenny’s (1986) framework and generalised structural equation modelling. Findings Board gender diversity (BGD) is positively associated with ESG performance, particularly when women hold senior leadership positions such as CEO or board chair. The results also indicate post-critical mass effects. SCs partially mediate this relationship, with the strongest mediation effect found for female board chairs. In addition, OCF opacity moderates these dynamics by weakening the effects of BGD and female board chairs on ESG performance, while amplifying the influence of female CEOs in opaque reporting environments. Research limitations/implications In spite of its contributions, this study has limitations that open avenues for future research. First, the analysis may suffer from survivorship bias, as FTSE 100 firms could differ from those entering or exiting the index, limiting generalisability. Second, the binary measure of SC presence may overlook variations in mandate, expertise or activity. Third, while ESG scores are becoming standardised, they may still reflect provider-specific noise. Unobserved time-varying factors, such as corporate culture or stakeholder pressure, may also affect both governance and ESG outcomes, and some effects may reflect broader industry trends not fully captured by fixed effects or controls. Practical implications The findings suggest that ESG performance improves most effectively when women occupy leadership roles on boards, financial reporting is transparent and SCs are empowered to translate board intent into operational governance. Social implications This study advances gender equity, stakeholder trust and corporate responsibility, showing board diversity as both fairness and sustainability drivers. Originality/value This is one of the first studies, to the best of the author’s knowledge, to examine the joint effects of BGD, OCF opacity and SCs on ESG performance, highlighting how composition, transparency and governance interact to shape sustainable corporate behaviour.