This study examines the market reaction to warrant issuances on the Stock Exchange of Thailand during announcement, ex-warrant, and completion periods. The study covers warrants offering from year 1999 to 2011. The positive cumulative abnormal returns (CARs) are found during announcement day to post-announcement period. Notably, warrants with some certain characteristics yield greater positive return are warrants of the firms which offers multiple warrants for an issuance day, in-the-money warrant, and unequal exercise ratio. In contrast, the negative CARs are discovered during pre-ex-warrant period to ex-warrant day. Warrants of the firms issuing multiple warrants on an issuance day, in-the-money warrant and equal exercise ratio are variables those strongly followed negative direction during ex-warrant period. For completion period, CAR has negative relationship to warrant issuances. Considering on trading volumes by investor types, there is positive relationship between foreign investor trading direction and CAR, while retail investors behave in the opposition to CAR. Therefore, this study confirms trade imbalance existence which could happen due to asymmetric information among well-informed and uninformed investors.