The name has been decided upon after input from staff at both companies. An in-house design team at Capital Radio is now at work on the new brand identity for the company.
However, the name will have to be approved by shareholders at an extraordinary general meeting, the date of which is yet to be confirmed.
Ralph Bernard, executive chairman of GWR, said: "The name GCap Media retains elements of both the Capital Radio and GWR brands and reflects the important contribution both businesses will make to the merged group."
Earlier this month, the Office of Fair Trading approved the £700m merger of the companies, after Capital agreed to sell 106 Century FM, a Nottingham-based station.
The deal will create the UK's biggest radio company, controlling 40% of the radio advertising market. The merged group will own one national station, 55 analogue stations and 93 digital stations, reaching approximately 18m listeners.
Bernard said: "This is a pivotal time for commercial radio as advances in digital technology open up new opportunities, and GCap Media will have greater scale and financial resources to take full advantage."
Following the merger's completion, Bernard, executive chairman of GWR, and David Mansfield, chief executive of Capital Radio, will take on the same respective roles in the merged company.
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