This research investigate the differences of effect a positive rumor (good news) caused to stock performances of corporate with good corporate governance and corporate without good corporate governance in the Indonesian capital market. The results of this research show that a positive rumor can cause a positive and significance abnormal return of stock prices. Paired sample t-test gives the result that there are no difference of effect between before a rumor being published and after the rumor being published on average stock abnormal return of company with GCG, while the contrary happens to company without GCG. Other result on this research also shows that investors react to the published rumor by trading accord the rumor information content and there is also a change in liquidity after the rumor being published.
