The Stock Price Behavior of Participation Index Firms: The Event Study on Borsa Istanbul

The index type created from the stocks of companies operating in accordance with Islamic principles is called “participation index”. In this study, whether the inclusion of companies operating in Borsa Istanbul National Market and in accordance with Participation Banking principles in the BIST Participation 30 Index had an effect on the price of stocks, was analyzed with the event study method. As a result of the analysis, it was observed that the cumulative abnormal returns had been on decline before the companies were included in the participation index, and the decline continued on the day of the event and the following days. The findings obtained are meaningful and typical for all relevant economic units, especially for investors and market makers.