Do Commercial Ties Influence ESG Ratings? Evidence from Moody's and S&P

We provide the first evidence that conflicts of interest arising from commercial ties lead to bias in environmental, social, and governance (ESG) ratings. Using the acquisitions of Vigeo Eiris and RobecoSAM by Moody's and S&P as shocks to the commercial ties between ESG rating agencies and their rated firms, we show that, after their acquisitions by the credit rating agencies (CRAs), ESG rating agencies issue higher ratings to existing paying clients of the CRAs. This effect is greater for firms that have more intensive business relationships with the CRAs, but weaker for firms with more transparent ESG disclosures or higher long-term institutional ownership. The upwardly biased ESG ratings help client firms issue more green bonds and enable the CRAs to maintain credit rating business. Finally, the upwardly biased ESG ratings are less informative of future ESG news. Overall, the business incentives of rating providers appear to engender ESG rating bias.