ISATR/TURKIYE IS BANKASI A.S.

It has been approved by Banking Regulation and Supervision Agency that; the credit risk-weighted assets used in the calculation of our regulatory capital requirement will be determined using the Internal Ratings-Based (IRB) Approach effective from the July 2026 reporting period. Within the framework of this application, the capital adequacy ratios calculated under the new methodology will be included in the financial reports to be disclosed to the public starting from the September 2026 period.

Had the aforementioned approach been utilized in the capital adequacy calculation as of March 2026, the most recent publicly disclosed financial reporting period, the impacts on both bank-only and consolidated capital adequacy ratios would have been positive. The magnitude of these impacts is presented in the table below :

This is the translation of the Turkish public disclosure made by Türkiye İş Bankası A.Ş. through the Public Disclosure Platform, under the Material Events Guideline prepared in accordance with the Communique of Material Events, numbered II-15.1. According to the Material Events Guideline and the regulations, the Turkish public disclosure shall prevail.