BBC News - Mariko Oi

Saudi Arabia's Public Investment Fund (PIF) has agreed to buy a 10% stake in Heathrow airport from Spanish infrastructure giant Ferrovial.

Another 15% in its parent company, FGP Topco, will be sold to France-based private equity fund Ardian.

Ferrovial, which has owned a stake since 2006, announced that the deal was worth £2.37bn ($3bn).

The transaction is still subject to regulatory conditions, according to the firm.

If approved, the deal would end Ferrovial's investment in the UK airports' operator which started at 56% but was reduced to 25% by 2013.

Other stakeholders in FGP Topco include Qatar Investment Authority, Caisse de dépôt et placement du Québec, Singapore's GIC, Australian Retirement Trust, China Investment Corporation and Universities Superannuation Scheme.