Price effects of changes to size sub-indexes on the Australian stock exchange: An event study.

This paper examines whether the general effect of index inclusion is present in relation to inclusion in the size sub-indexes on the Australian Stock Exchange. Results show that positive abnormal returns may be made for additions in the 30 days prior to the announcement window. However cumulative abnormal returns for the next 90 days are negative. Results of deletions are not so clear, and it is apparent that over the 120 day event window, deletions show a positive CAR. In relation to the overall AOI, it appears that the index effect is stronger for the AOI as reported by Howard and Chan (1999), than it is for the sub-indexes examined here.