Schwarz, who was instrumental in leading the Capital/GWR merger recently passed by the Competition Commission, decided to leave the company following the merger, agreeing that her time at the broadcaster had come to an end.
A Capital spokeswoman confirmed: "Nathalie is leaving at the end of the month of her own accord and as yet there are no plans to replace her."
Schwarz joined Capital as company secretary and head of legal affairs in 1998 before being promoted to strategy and development director in 2002. She was also appointed to the Capital Radio board in December 2003.
Media regulator Ofcom and the Office of Fair Trading gave the go-ahead for the £700m merger between Capital Radio and the GWR Group on December 22.
Capital Radio chairman Peter Cawdron said: "Nathalie has been an influential figure both at Capital and within the radio industry and has made a significant contribution to the group's progress."
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