Stansted, located in London, is the fourth-busiest airport in the United Kingdom, serving 18 million passengers in 2011, the BBC said.
Heathrow Airport Holdings was forced by the government's Competition Commission to put Stansted up for sale. Heathrow owns four British and Scottish airports, including London's Heathrow International.
The deal for Stansted is expected to close next month, the BBC said.
Manchester Airport Group, the new owner of Stansted, is owned by 10 borough councils from the Manchester area.