Saudi Arabia's sovereign wealth fund, the PIF, has taken a 10% stake in the UK's busiest airport, London Heathrow.

The Public Investment Fund has been broadening its portfolio in recent years, with sporting investments making headlines around the world - along with claims of 'sports washing'.

Spanish infrastructure group Ferrovial has sold its 25% stake after downsizing in 2013. The firm sold its stake in Heathrow Airport Holdings Limited for £2.4bn ($3.04bn).

“Over the last 17 years, we have been contributing to Heathrow’s transformation, together with our fellow shareholders, achieving some excellent milestones throughout our long-term role as investor,” said Luke Bugeja, CEO of Ferrovial Airports.

Bugeja highlighted capacity and operational wins during Ferrovial's tenure, including "...expanding its capacity with the construction of Terminal 2 and improving its operational performance."

The PIF bought 10%, with the remaining 15% sold to French private equity group Ardian.

Heathrow is not the PIF's first transport investment. It currently holds stakes in ride-hailing app Uber, the Saudi Public Transport Company (SAPTCO), The Helicopter Company, and Riyadh Air.