The Informational Value of Corporate Credit Ratings

This thesis examines the quality of credit ratings issued by the three major credit rating agencies - Moody’s, Standard and Poor’s and Fitch. If credit ratings are informative, then prices of underlying credit instruments such as fixed-income securities and credit default insurance should change to reflect the new credit risk information. Using data on 246 different major fixed income securities issuers and spanning January 2000 to December 2011, we find that credit default swaps (CDS) spreads do not react to changes in credit ratings. Hence credit ratings for all three agencies are not price informative. CDS prices are mostly determined by historical CDS prices while ratings are mostly determined by historical ratings. We find that credit ratings are marginally more sensitive to CDS than CDS are sensitive to ratings.

Effects of credit rating change on risk-taking

This thesis investigates whether there are changes in risk-taking behavior following an upgrade or downgrade in credit ratings. Research on effects of rating changes on capital markets is well-documented but the literature on how rating changes may affect firm behavior is sparse. Following, a downgrade in credit rating, managers may increase risk-taking to improve their overall performance or reduce risk-taking following upgrades to ensure that their performance is assessed more on the basis of what they may deem success in the form of an upgrade. Using a sample of firms trading in the U.S from 1994-2013, we find evidence of change in risk-taking behavior. We use cross-sectional regressions and matching using propensity scores and Barber and Lyon (1997) methodology to measure changes in risk-taking and we do find evidence of changes in managerial risk-taking behavior. Furthermore, we find that the direction of change (increase or decrease) in some cases is dependent on the type of measure rather than the type of rating change.