Muhammad Sriwahyudi Suliswanto


The purpose of this research is to know significant of abnormal return stock mass LQ45 from bankruptcy announcement of Lehman Brothers United States, to know the differences of abnormal return stock mass LQ45 in after and before the event, and to know the pattern of average abnormal return stock mass LQ45 between company of PMA and of PMDN.
The method that used in this research is event study, because it useful in testing the information content from an announcement and also it can be used to test market efficiency of semi strength. The result of this research showed that there were significant of abnormal return, for period before event that is 3, 8, 9, 12 September 2008 there are positive significant and to the 5, 10, 11 September 2008 there are negative siginificant. While for period after event of positive significant happened on 17, 19, 22, 25, 6 and negative significant happened on 16, 18, 23, 24, 26. But, not happened difference by significant between after and before event.
Beside that, from this research can be known that market need long time in reaction to new balance price posed at still there are abnormal return come up with day t+9 that is on 26 September 2008. This matter indicate that market not yet is efficient of semi strength informationly. While for speculative behavioral Pattern of investor to company of PMA and of PMDN is mostly same, but at t+1 degradation of AAR at PMA company is lower that is -0,15196 or 15,19 % if it compared to PMDN company that is -0,10518 or 10,52 %.

Keyword : Event Study, Reaksi Pasar Modal, Abnormal Return, Kebangkrutan Lehman Brothers


Event Study; Reaksi Pasar Modal; Abnormal Return; Kebangkrutan Lehman Brothers