Dixons Carphone has made a lacklustre start to life with the shares losing more than 3% after their first day's trading.
Speaking at the opening of one of the new retail group's first hybrid stores in central London, its chief executive, Sebastian James said: "There will be ups and downs and it is going to be bumpy but we are totally convinced that this is going to be a fantastic business."
The merger with Carphone Warehouse hands Dixons a slice of the lucrative mobile market as well as a partner to help sell household gadgets – such as fridges, and TVs – that are increasingly connected to the internet and controlled by smartphone apps.
With the key Christmas trading period on the horizon, James said the company had to hit the ground running with the integration of several teams, including finance and legal, already pushed through. The merger will result in head office job losses as two headquarters become one but will create jobs in the enlarged group's 3,000 stores. The deal is predicated on reducing combined annual running costs by £80m within four years. "We need to move extra quickly to get things we can do now, done," he said.
The group has installed Carphone Warehouse branded mobile departments in seven Currys and PC World stores and another 23 will open by Christmas.
The pace of change will accelerate in January when 10 stores a week will be refurbished. But the refurbishment programme will not touch the 160 stores where Phones4U has a presence under a contract that expires in May.
The shares closed down 10.9p at 337p on Thursday.