Turkcell is a converged telecommunication and technology services provider, founded and headquartered in Turkey. It serves its customers with voice, data, TV and value-added consumer and enterprise services on mobile and fixed networks. Mobile communication in Turkey began when Turkcell commenced operations in February 1994. Turkcell then signed a 25-year GSM license contract with the Ministry of Transportation on April 27, 1998. Since then, it has continuously increased the variety of its services based on mobile voice and data communication, as well as on its quality levels, and as a result, its number of subscribers. Turkcell's shares have been traded on the Borsa Istanbul (BIST) and New York Stock Exchanges (NYSE) since July 11, 2000, and it is the only Turkish company to be listed on the latter exchange. Turkcell is also quoted on the Borsa Istanbul Sustainability Index.