Ofgem said around 290,000 customers will stay on the same tariffs and all outstanding credit balances will be honoured by OVO Energy, including money owed to both existing and former customers.
Customers will continue to be billed by Spark and contacted by its customer service staff as OVO Energy has bought the supplier’s brand.
They will be contacted over the coming days about the changes, at which point customers can change their tariff or switch supplier if they wish to do so.
Spark Energy became the seventh energy company to cease trading this year, following Extra Energy’s demise prior to that.
Mary Starks, Ofgem’s Executive Director for Consumers and Markets said: “I am pleased we have appointed OVO Energy and that Spark Energy’s customers will be offered the same tariffs they are already on. Their credit balances will be honoured and their energy supply will continue as normal.
“OVO Energy, under the Spark Energy brand, will be in contact with customers over the coming days with further information. Once the transfer has been completed, customers can shop around for a better deal if they wish to.”
Stephen Fitzpatrick, CEO and Founder of OVO Energy added: “The energy sector is going through a major change and many companies, big and small, are struggling to adapt. We are delighted to have been able to bring Spark into the OVO Energy Group, securing a good outcome for their customers and the team.
“We will combine OVO’s innovative technology and focus on customer experience with Spark’s unique network of partnerships to bring greater products and services to more householders around the UK.”