Informed investors' market wealth is influenced to a greater extent around the corporate announcements. Therefore, the present study attempts to examine the effect of rights issue announcement of NSE CNX 500 stocks on stock prices during January 2006 to December 2013. Event study methodology was adopted in this study to examine the effect surrounding the sixty days of the announcement. AR, AAR and CAAR were calculated and t tests were carried out to test the significance. Time window analysis was done to find the event window which maximizes the shareholder returns.The findings in respect to rights issue announcement by CNX 500 stocks; it was identified that investors were able to get positive abnormal returns in the pre event window than post event window. It was also found that rights issue announcement had resulted with significant negative impact on stock prices around announcement.