Mandate or Market? Climate-Disclosure Regulation and the Quality of Corporate Climate Governance: Evidence from Staggered Adoption Across Four Economies

Climate-related disclosure has moved rapidly from a voluntary practice to a legal obligation, yet whether mandates improve the substance of corporate climate governance—rather than the volume of reporting—remains an open question. We exploit the staggered introduction of climate-disclosure mandates in the United Kingdom (2022) and France (2025), with the United States and Australia serving as never-treated and not-yet-treated comparison groups, to estimate the effect of mandatory disclosure on structured climate-governance quality. The outcome is the Transition Pathway Initiative (TPI) Management Quality score, an externally assessed 0–5 staircase of climate-governance practices, observed for 837 listed firms over 2015–2025 (2841 firm-year observations). Using two-way fixed effects, Sun–Abraham and Callaway–Sant’Anna estimators implemented in RStudio, we find no statistically significant effect of disclosure mandates on climate-governance quality: the preferred Callaway–Sant’Anna estimate is 0.082 levels (95% CI −0.221 to 0.385), precise enough to rule out effects larger than about 0.4 levels (≈0.4 standard deviations). Meanwhile, never-mandated US firms improved from a mean Management Quality of 1.4 to 3.1 over the decade, converging toward mandated jurisdictions. An anticipation-adjusted specification yields a positive and significant effect, but it benchmarks against pandemic-year assessments and should be read with caution. Disaggregating the score into its underlying indicators shows that board-level oversight and basic disclosure are near-universal among mandated firms, whereas transition-planning and capital-alignment practices remain rare in every jurisdiction, locating the unfinished governance agenda at the top of the staircase. The evidence suggests that disclosure mandates largely codified governance practices that investor- and market-driven pressures had already diffused, implying that regulators should pair disclosure requirements with substantive transition-plan obligations if the policy goal is governance change rather than transparency alone.