Mergers have been an increasing phenomenon in Vietnam market recently, in particular banking industry. This study examined the main benefits of specific banking mergers in Vietnam. In line with the literature, the study also addresses the issue of whether or not we can infer the effects of banking mergers to the market by observing market response. To solve these questions, the research investigated the reactions of market to announcements of the two official banking mergers in Vietnam. The seemingly unrelated regression (SUR) method is applied as. The data set includes daily share price of the nine banks, which are listed in Vietnam stock market and the market index for a period of 182 trading days surrounding each event day.