ESG Controversies and Corporate Performance: A Critical Appraisal of Rating Methodologies and Empirical Evidence

ESG controversies have become relevant signals in capital markets. However, controversy measurement is not strictly regulated, and evidence on whether and under which conditions such events affect firm-level performance remains fragmented and lacks quality appraisal. Addressing these concerns, this manuscript integrates a document-based comparative assessment of publicly disclosed controversy methodologies used by leading ESG data providers, with a systematic review of empirical research on ESG controversies and corporate performance. The document-based comparison shows that controversy is not a single stable construct. Rather, providers differ significantly in rated object, aggregation rules, materiality perspective and time dimension. Most empirical studies find negative market reactions and higher risk or financing costs following controversy identification. Quality appraisal indicates that the evidence base is generally of moderate quality but unevenly reported, limiting reproducibility and generalizability. Overall, the findings support treating ESG controversy as a consequential but methodologically heterogeneous signal.