The evidence in this paper suggests that downgrades by both Moody's and Standard and Poor's are associated with negative abnormal stock returns in the two-day window beginning the day of the press release by the rating agency. Significant negative abnormal performance can still be detected after eliminating observations containing obvious concurrent (potentially contaminating) news releases. There is little evidence of abnormal performance on announcement of an upgrade. Significant abnormal returns are associated with announcements of additions to the Standard and Poor's Credit Watch List, if either a potential downgrade or a potential upgrade is indicated.

This paper contains evidence of a significant negative stock price reaction to media disclosures of ‘subject to’ qualified audit opinions. Disclosures of qualifications in the financial news media (the Wall Street Journal and the Broad Tape) are rare relative to the frequency of audit qualifications. Other studies do not detect an impact of qualified opinions on stock prices. None of the explanations for the difference in the results between this study and prior studies is consistent with the data. We are unable to draw strong inferences because we cannot identify the selection process that produces the sample of media disclosures.