Spanish infrastructure group Ferrovial has offered Heathrow Airport Holdings £800 million for British airports Aberdeen, Glasgow and Southampton, according to Spanish financial newspaper Expansión, which cited industry sources.
One industry source told Reuters that an offer had been made, but declined to give further details.
Ferrovial declined to comment.
The Spanish company holds a 25% stake in HAH, previously BAA, which is owned by a consortium including Britannia Airport Partners, Singapore's GIC, Qatar Holding and Alinda Capital Partners.
Ferrovial bought Heathrow and a number of other British airports as part of its acquisition of BAA in 2006 for £10.3 billion.