Sustainability reporting: An application on companies in the Bist sustainability index

In this study, the formation of sustainability and sustainability reporting and the necessity of sustainability indices are presented. The benefits of entering the sustainability indices on enterprises in terms of their economic, environmental and social performance are important for businesses and then for their stakeholders. For this reason, in the first period of Borsa İstanbul (BIST) Sustainability Index, which was established in 2014, it has been tried to measure the change in financial performance of the 15 companies included in the index in the sustainability index. The measurement area is based on the 12-quarter periods before entering the index and the 12-quarter periods after entering the index. The data obtained with the ratios determined from the balance sheet and income statements published by the companies are analyzed by TOPSIS method and converted into a single score in terms of periods. Due to the differences in the balance sheet and income statements of these 15 enterprises, the enterprises were separated into four banks and 11 other banks. The arithmetic averages before and after the index were compared using TOPSIS. In the comparison made by banks in terms of periods, it was observed that entering the sustainability index did not cause an increase in the financial performances of the banks, but in the comparison made by non-bank enterprises, it was observed that entering the sustainability index of these enterprises caused an increase in their financial performance. In general, when the financial performances of all 15 enterprises are measured, it is determined that the financial performances of the enterprises increased in the post-index period, thus entering the sustainability index has a positive effect on the financial performances of the enterprises.