David Sullivan and David Gold have acquired 50 per cent of West Ham United and with immediate effect will have operational and commercial control of the football club.
The deal, which was concluded late last night, values the club at £105 million.
Mr Sullivan, a lifelong West Ham fan, was brought up in Hornchurch and studied economics at Queen Mary College, Mile End. He said: "I have been interested in running West Ham United for 20 years and I can't wait to start work.
"I enjoyed running Birmingham City for 16-and-half years, but everyone there knew my true love was always West Ham United.
"It will be an immense privilege to lead this great football club and more importantly its supporters.
"Our first priority has to be securing the Premier League status of West Ham. I believe the players at this club have shown great commitment in trying circumstances and the new board and I will get behind them in every way we can.
"We will also look to bring in new players to supplement the squad where needed once we have met with the manager."
Mr Gold and Mr Sullivan will join the club as joint chairmen and their former colleague Karren Brady will be appointed vice chairman.
Mr Sullivan added: "I would like to thank former executive chairman Andrew Bernhardt and CB Holding who assumed control of the club in difficult circumstances through no fault of their own.
"Our long-term aim will be to put the club on a stronger financial footing. I believe with our new board we have the expertise and experience to do just that and bring the good times back to this great football club.
"West Ham United need stability after all the recent upheavals. We appointed four managers and parted company with two at Birmingham in 16 years. We believe in our managers and give them the time and support they need.
"The club is now back in the hands of East Enders, people who understand the community and its passion for the Hammers. I believe that depth of feeling will also bring us through what has been a difficult period."
Mr Gold's connection with the club also runs deep; he was born across the road from Upton Park at number 442 Green Street and also represented the club as youth team player, including scoring the winner against Glasgow Youth in 1951 as a 'nippy left winger'.
He said: "Finally I have come home to the club I love with all my heart. This is an incredibly sweet moment but we have to put the romance aside now and get on with a difficult job."
Mr Gold and Mr Sullivan will hold a media conference at the Boleyn Ground, Upton Park from 12.30pm today. Accredited media representatives are invited.