Ovo Energy has finally completed the migration of 3.5 million customers from SSE, more than four years after the deal was first announced, Utility Week has learnt. The energy retailer announced in September 2019 that it had agreed a deal to purchase the domestic arm of SSE, at the time one of the big six, for £500 million. It subsequently completed the deal in January 2020, with Ovo having license to use the SSE brand until the end of 2023.