Only one of Xfm Wales' original employees remains with the station, which was relaunched as Nation Radio on 16 June.
Eleven programming staff have been dismissed, according to a former GCap employee. However, Ben Evans has remained at Nation Radio, having made the move from programming to presenting, taking over the station's 1-3pm slot.
Before its sale, GCap employed three dedicated sales people to sell Xfm Wales, all of whom are no longer employed by Nation Radio.
One was reallocated to GCap and the other two decided to leave to pursue other careers, before being made redundant.
Martin Mumford, Town and Country Broadcasting group managing director, said: "We don't discuss our staffing. It's an internal matter."
Xfm South Wales was launched by GCap Media at the end of 2007, following the earlier launches of Xfm Manchester, Scotland and London.
The station was on the market since 11 February, when former chief executive Fru Hazlitt announced plans to sell all three non-London Xfm stations.