The Extent of Informational Efficiency in the Credit Default Swap Market : Evidence from Post-Earnings Announcement Returns

Under semi-strong market efficiency future returns are unpredictable from previously released information. We test the degree of semi-strong form market efficiency in the credit default swap (CDS) market by examining the relationship between subsequent CDS returns and previously announced quarterly earnings surprises and quarterly accruals, both of which have been the source of stock market anomalies. We conduct our analysis over three time periods: (1) prior to the credit crisis of 2007 and 2008, (2) during the credit crisis and (3) after the credit crisis. Prior to the credit crisis, the CDS market was efficient, exhibiting no systematic relation between subsequent CDS returns and previously announced accounting information. During the credit crisis, however, we find that both quarterly earnings surprises and quarterly accruals are associated with systematic patterns in subsequent CDS returns that are consistent with underreaction to both measures. In the immediate aftermath of the crisis, the pattern reverses with the CDS market overreacting to both measures although the overreaction dissipates in later quarters. Collectively, our results indicate that the CDS market is efficient during periods of relative economic stability but call into question its resilience during less stable economic periods