The value of the deal has not been disclosed, though previous reports have estimated it could be worth as much as £600m. The takeover will be checked by regulators, before any approval is granted.
Both firms said there would be no change for customers while regulators reviewed the deal and that tariffs – such as fixed deals – would be honoured for the duration of the contract.
Emily Seymour, energy editor at consumer group Which?, said: “If you’re an Ovo customer, don’t panic, your gas and electricity supply will continue as usual.
“E.On have assured customers that existing tariffs will be honoured in full and service will continue unchanged. You don’t need to do anything and you’re still able to switch supplier if you wish.”
Sabrina Hoque, from the price comparison website Uswitch, said that Ovo customers might be nervous.
But she added that, even if the deal were approved, credit balances would be protected as customers would transferred across automatically.
