After nine failed suppliers, major takeovers and a price cap on bills, the energy sector has faced another bruising year which seemed to mark, once and for all, the end of the Big Six.
SSE swung from a £285 million pre-tax loss in the first six months of 2018 into a £129 million profit this year, the company said on Wednesday in the first results since selling its energy supply arm to challenger brand Ovo, a deal which will be completed early next year.
The competition watchdog has said it is mulling an investigation into Ovo energy's acquisition of SSE's retail business.
Overall satisfaction with energy suppliers has fallen for the second year running after customers were battered by price rises and nine small firms collapsed, according to a survey.
Japan's Mitsubishi Corporation is to acquire a 20% stake in British energy supplier Ovo for around £200 million to fund its international expansion.
Challenger suppliers have topped an annual customer ranking of energy companies but overall satisfaction has dropped for the first time since 2011.
The UK's electricity and gas regulator has launched an investigation into Ovo Energy over information the company gave some customers.