Local campaigners estimate that the deal will be worth £400 million to Parkview and its investors.
The future of the vast planning permission secured for for a group of architects including Grimshaw and Arup Associates is now up in the air as the new owners are expected to reassess everything.
Parkview, which has a 37.5 per cent stake in the new ownership group, has promised to press on with winning planning permission to demolish the power station's famous chimney stacks and then rebuild them.
REO chairman Ray Horney said: 'We are delighted to be involved in a project that presents both a magnificent property development opportunity and challenge.
'The power station itself is a building that is a much-loved part of London's heritage on a site, which by virtue of its size and location, offers an extraordinary development opportunity. No comparable site exists in central London.'
Battersea Power Station Community Group member Keith Garner has reiterated his previous accusations about Parkview. He said the developer had deliberately allowed the building to get into 'a very bad state'.
He also said he hoped that the new owner would take a different approach and make an immediate start to the repairs, rather than continue Parkview's 'policy of neglect'.
But Victor Hwang, President of Parkview said: 'Our first priority has always been to ensure that the regeneration of Battersea Power Station would be seen through to completion.
'We have given a great deal of effort to create a world-class project in one of the world's greatest cities.
'We have, over time, been in numerous discussions to seek the right development partner for the project to continue and we believe that REO is the right choice.
'To see this development through the construction phase to completion requires vision, skill, finance and experience in urban regeneration on this scale,' he added.