The Impact of a Rating Agency's Private Information and Disclosed Causes of Rating Downgrades on Insurer Stock Returns

Abstract

Existing studies document that bond and insurer rating downgrades are associated with negative abnormal returns but generally do not consider the reasons for the downgrade disclosed or implied in the downgrade announcement. Using hand-collected press releases (downgrade announcements) of A.M. Best Company (Best) for a sample of publicly traded insurance firms during the period 1996–2012, we classify and analyze downgrades based on the disclosed causes of the downgrades and whether the rating agency has implied reliance upon unfavorable private information or opinion. We find that during the three-day event window (−1, +1), rating downgrades overall generate a statistically significant cumulative average abnormal return (CAAR) of negative 7.76%. A significantly more negative CAAR of negative 11.46% is found for “financial-prospects-deterioration” downgrades with the perceived presence of Best's private information or opinion. For downgrades without any indication of Best's private information or opinion, the CAAR is negative 3.35%, which is significantly different from zero but significantly less negative than the CAAR of downgrades where private information or opinion is indicated. Downgrades with reported causes other than deterioration of a firm's fundamental financial performance or condition, such as increases in financial leverage and increased business risk taking, produced statistically significant CAAR of negative 3.19% during the (−1, +1) three-day event window, which is also significantly less negative than the CAAR of downgrades where private information or opinion is indicated. Our results provide evidence that downgrades where private information or opinion is likely and downgrades due to a decline in fundamental financial profiles contain more value-relevant information than other types of downgrades.