The Manchester Airport Group (MAG) has completed its £1.5bn acquisition of Stansted Airport, from Heathrow Airport Holdings, the group confirmed.
MAG has added Stansted to its existing portfolio of Manchester, East Midlands and Bournemouth airports.
Funding came from Industry Funds Management (IFM), which has a 35.5% stake in the enlarged group.
Built in 1991, Stansted's main traffic is provided by budget airlines such as Easyjet and Ryan Air flying to Europe.
Sir Richard Leese, leader of Manchester City Council, a MAG shareholder, said: "MAG is a key driver of jobs and growth in the North of England and the acquisition of Stansted will help us deliver maximum value for Manchester City Council and the other local authority shareholders.
"A larger, stronger MAG will benefit the whole region."
Charlie Cornish, chief executive of MAG, said: "We aim to help fulfil its [Stansted] potential in the London market and bring more choice to its passengers in the years ahead."
Christian Seymour, head of infrastructure, Europe, at IFM called the deal "a landmark acquisition" for the investment company calling it the "culmination of 18 months' work developing a strong, long term partnership with MAG".