Rewriting History II: The (Un)Predictable Past of ESG Ratings

Rewriting History II: The (Un)Predictable Past of ESG Ratings

Florian Berg, Kornelia Fabisik, Zacharias Sautner

Series number :

Serial Number: 
708/2020

Date posted :

November 10 2020

Last revised :

November 19 2020
SSRN Share

Keywords

  • ESG ratings • 
  • ESG investment • 
  • CSR

The explosion in ESG research has led to a strong reliance on ESG rating providers. We document widespread changes to the historical ratings of Refinitiv ESG, formerly ASSET4, a key rating provider. Across two downloads in 2018 and 2020, we document large rewritings in ESG ratings, which are systematic and partially related to firm characteristics.

The retrospective rating changes have important implications for researchers and investment professionals. Depending on whether the original or rewritten data are used, rankings and classifications of firms into ESG quantiles change. We demonstrate that these changes affect tests that relate ESG ratings to stock returns.

Authors

Real name:
Florian Berg
Dr.
Real name:
Kornelia Fabisik
Academic Member
Frankfurt School of Finance & Management