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 :

January 07 2021
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 rater. Across two downloads in 2018 and 2020, we document large rewritings in ESG ratings, which are systematic and related to past performance.

The retroactive rating changes have 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 returns. We further show that the data rewriting is an ongoing rather than a one-off phenomenon.

Authors

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