The radio company created by the merger of Capital Radio and GWR began trading on Monday with a warning that it was taking a "cautious view" of the market.
The combined radio group hopes to reach 17 million adults
Company Gcap also revealed a 17% fall in April revenues - with no immediate improvement in sight.
The UK's largest commercial radio firm, which has 40% of the radio advertising market, said advertisers were spending less and consumer confidence was weak.
Capital Radio shares fell recently as rival Heart FM added more listeners.
Last week, figures from radio trade body Rajar showed Heart FM leapfrogged rivals Capital FM and Magic FM between January and March, notching up a 7% share of total listening.
On Monday, Capital Radio said the UK election and the timing of Easter this year had affected its revenues, which were down 21%, while those of GWR were down 15%.
"The Gcap Media board is taking a cautious view on overall market conditions and currently expects the principal factors that impacted April to continue in May and June," the company said.
Shares in the merged group fell 7.3% on Monday. The stocks will remain listed under the name Capital Radio until Tuesday.
Unveiling Capital Radio's figures for the six months to 31 March, chief executive David Mansfield said it had been "difficult in terms of our trading environment".
However he said "significant strategic progress" had been made for the group. "The highlight has been the successful formation of Gcap Media, where we will see operational benefits from the early integration of our two management teams," he added.
The results showed Capital Radio revenues down 1% to £59m ($112m), and underlying profit before tax dropping to £10.8m from £12.1m last year.
The group also said it would sell 106 Century FM in the East Midlands to Chrysalis Group for £29.5m, to meet UK competition regulations.
Station to station
The deal, after the Communications Act relaxed the rules on tie-ups between radio companies, brings Capital FM, Classic FM and Xfm together and creates one of the UK's biggest commercial radio groups.
UK'S BIGGEST RADIO GROUPS
Capital/GWR - owner of Capital FM
Chrysalis Radio - Heart FM
Emap - Kiss FM and Magic FM
GMG Radio Holdings - Jazz FM
Scottish Radio Holdings - Radio Clyde and Radio Forth
The Wireless Group - Talksport
SMG - Virgin
Source: Commercial Radio Companies' Association
It will reach 17 million adults - by pooling 55 local analogue radio stations, 93 digital ones and one national radio station - and account for 35% of the UK commercial radio audience.
It also gives the group a greater share of the UK commercial radio advertising market, thought to be worth £660m a year.
The companies believe the tie-up will enable them to play a pivotal role in the development of digital radio and accelerate the growth of commercial radio's share of listening relative to the BBC.
The merger was implemented by Capital Radio issuing new shares: GWR shareholders getting 60.2 new Capital Radio shares for every 100 GWR shares they own.