Sonova Holding AG is an internationally active Swiss group of companies headquartered in Stäfa that specializes in hearing care. The Sonova group operates through its core business brands Phonak, Unitron, Hansaton, Advanced Bionics, AudioNova and Sennheiser. It is one of the largest providers in the sector worldwide. The group and its brands hold 24% of the global hearing aid market in sales. As of 11 September 2022, Sonova was a component of the Swiss Market Index. Wikipedia