Michaelides, Alexander, Andreas Milidonis, George P Nishiotis, and Panayiotis Papakyriakou.
Journal of Financial Economics 116 (3): 526-547.
Publication year: 2015
  • Rating agencies consult with local government officials several days prior to official announcements of sovereign debt rating changes.
  • This consultation period makes information leakage likely.
  • We find evidence of information leakage: statistically and economically significant, negative daily abnormal equity index returns before sovereign debt rating downgrade announcements.
  • These effects are more pronounced in countries with lower institutional quality, and persist during times with no downgrade rumors and no concurrent bad news in general.
  • A post-announcement reversal consistent with overreaction to pre-event downgrade rumors highlights the adverse effects of such leakage.
  • Information leakage before announcements should be a policy concern for capital market regulators around the globe.