The company has agreed to buy a portfolio of assets, also including East Surrey Pipelines, from the Eiser Global Infrastructure Fund.
The acquisition also includes a stake in Italian waste treatment and disposal company Herambiente, as well as shares in four Spanish concession companies, two operating shadow toll roads and two operating bus terminal interchanges in Madrid.
Belfast City Airport is the airport closest to Northern Ireland’s capital and served 2.7m passengers in 2015, while East Surrey Pipelines is the second independent gas transporter and third largest independent electricity network operator in the UK.
A new vehicle managed by 3i will have £700m available to fund the initial acquisition and to provide capital for follow-on investments across the portfolio. The company will invest around £36m in the vehicle alongside pension fund investors APG and ATP.
Under the agreement, existing investors in the Eiser Fund are offered the opportunity to participate in the new vehicle.