Energy supplier Octopus Energy is to buy its smaller competitor Bulb, after the UK government approved a deal.
Bulb collapsed last year after rising gas and electricity prices, and has since been run by the government.
Its 1.5 million customers will not experience "any change or disruption to their energy supplies", the government said.
The deal is expected to be completed by next month.
Business Secretary Grant Shapps said the move will bring "vital reassurance and energy security to consumers across the country at a time when they need it most".
Octopus had previously requested £1bn in public funding for the deal, but the government announcement made no mention of the money involved in the deal.
The statement said that "due to high market volatility it is impossible" to forecast the true cost of Bulb.
Octopus said the move would bring "an end to taxpayer losses", adding it was "paying the government" to take on Bulb's customers.
London-based Bulb was the biggest of more than 30 energy companies that collapsed last November following a spike in wholesale gas prices, which was partly caused by Covid restrictions ending and has since been exacerbated by the war in Ukraine.
It was placed into "special administration", meaning it was run by the government through the regulator Ofgem. The special administration measure is only used if Ofgem is unable to find another company to take over an energy firm's customers.
The state bailout of Bulb had been forecast to cost the taxpayer around £2bn by next year. It was the biggest state bailout since the Royal Bank of Scotland collapse during the 2008 financial crisis.
Mr Shapps, who became business secretary this week by Rishi Sunak, said the move highlighted the government's "overriding priority" to protect customers. He added he would do everything he could to "ensure our energy system provides secure and affordable energy for all".
Octopus will continue to use Bulb's technology and branding "for a transitionary period", the government's statement said.
The company, which was founded in the UK in 2015, said that before the Bulb acquisition it served 3.4 million customers.
https://www.bbc.co.uk/news/business-63437352