A convertible bond (CB) is a hybrid security containing elements of both common stock and straight debt. Still, empirical investigations on CB issue announcements have failed to discern any pattern in the stock market reaction that is consistent with announcements of either common equity or straight debt issues. This study shows that (a) motives for issuing the CB and (b) its rating (and to a less extent the riskiness of the issuing firm) help explain the stock market reaction to CB issue announcements. Specifically, announcement of a CB issue with an explicitly stated motive for the use of proceeds, when coupled with a high (low) bond rating, generates a stock market response similar to a straight debt (common stock) issue. On the other hand, the preference of CB holders is dictated by the motive for the use of proceeds and the conversion premium. These findings highlight the critical importance of the motive of issue in determining reactions in both the stock and bond markets.