Do sustainable management standards mitigate ESG rating divergence? Evidence from Bloomberg and LSEG.

This thesis analyses the problem of ESG rating divergence, where different agencies assign conflicting scores to the same company. Such inconsistencies reduce the reliability of ESG ratings, creating difficulties for investors, managers, and policymakers. The study conducts and empirical analysis on 109 Fortune 500 manufacturing firms, comparing Bloomberg and LSEG scores, to evaluate whether the adoption of sustainability management standards (ISO 14001, ISO 50001, and the United Nations Global Compact) contributes to reduce disagreement. The results indicate that ISO 14001 shows no significant effect, ISO 50001 is associated to higher divergence due to heterogeneous adoption, while the UNGC appears to mitigate disagreement by providing a shared and symbolic framework. Additional factors, such as leverage and assurance, also influence rating divergence. Overall, the findings confirm that ESG disagreement is a structural phenomenon that cannot be resolved by a single mechanism, highlighting the need for greater coordination among standards, assurance practices, and rating methodologies to enhance the consistency and credibility of ESG ratings.