The Governance Pillar of ESG Criteria in Greece: Evidence from ATHEX ESG Index Firms and Implications for Sustainable Finance

Environmental, Social, and Governance (ESG) criteria are increasingly central to corporate transparency, risk oversight, and sustainable finance, yet evidence on the governance pillar in Greece remains limited. This study examines a pooled cohort of 68 firms appearing in the Athens Stock Exchange ESG Index during 2021–2023, with annual analytical samples of 66, 68, and 65 firms. Using annual reports, corporate governance statements, and sustainability disclosures, it evaluates board size, board independence, gender diversity, CEO–Chair structure, committee architecture, internal audit disclosure visibility, and external audit concentration. Board size remained stable. Proportional board independence peaked in 2022 and remained slightly above its 2021 level in 2023. The aggregate female board seat share increased, although the 2023 rise partly reflected a smaller denominator. CEO–Chair duality was persistent but non-monotonic, internal audit disclosure visibility changed only modestly, and top-two audit provider concentration increased in 2023. The findings are interpreted as selective governance institutionalization: visible, threshold-based arrangements adjust more readily than capability-intensive mechanisms involving authority, internal controls, specialist oversight, and assurance capacity. Greek, EU, and OECD benchmarks indicate partial regulatory readiness. The study provides a longitudinal governance baseline but does not estimate causal performance effects or certify firm-level legal compliance.