Turkcell Iletisim Hizmetleri A.S. (Turkcell) is one of the leading mobile telecommunications services providers in Turkey and the third largest global systems for mobile communications (GSM) operator in Europe in terms of number of subscribers. The company is engaged in providing mobile telecommunication services such as mobile audio and data services through its global systems for mobile (GSM) communications network. The company provides international services through contracts and agreements with 639 operators in around 208 countries under gnctrkcell and IsTcell brands. The services offered by the company are used by individual and corporate customers. Turkcell has presence internationally across Turkey, Ukraine, Belarus, Moldova, Georgia, Northern Cyprus, Kazakhstan, and Azerbaijan regions. The company is headquartered in Istanbul, Turkey.