Sonova Holding AG is an internationally active Swiss company headquartered in Stäfa that specializes in hearing care solutions. It is one of the largest providers in the sector worldwide. The group operates through its core business brands Phonak, Unitron, Hansaton, Advanced Bionics and AudioNova. On August 1, 2007 Phonak AG officially changed its name to Sonova Holding AG. Sonova Group and its brands hold 24% of the global hearing aid market in sales.