The sovereign CDS market has developed rapidly for two decades and currently has a gross notional amount of more than a trillion dollars. We document a strong momentum effect in this market, which cannot be explained by a large set of risk factors. These momentum returns are positively skewed and higher during recessions. Consistent with the interpretation that this momentum effect is due to investors’ initial underreaction to sovereign credit information followed by corrections, our evidence shows that the momentum returns tend to be higher during the months surrounding announcements of credit rating or outlook changes of the underlying countries.