Madrid-based Ferrovial, the world's biggest private investor in transportation infrastructures, is said to have lodged an £800million takeover bid for Glasgow Airport, along with Aberdeen and Southampton airports.
The firm, which also owns roads maintenance company Amey, is expanding in the UK and is said to be keen in doing a deal for the three regional hubs.
The airports are currently owned by Heathrow Airport Holdings (HAH), previously known as BAA.
Ferrovial already owns London Heathrow and has a 25% stake in HAH, which only recently sold Edinburgh Airport for £800m after it was forced by the Competition Commission to break up its stranglehold on the UK's airports. HAH was also forced to sell London Gatwick.
Ferrovial has refused to confirm or deny an opening bid of £800m for Glasgow, Aberdeen and Southampton airports. HAH officials were also staying silent, as were airport chiefs in Glasgow.
However, reports from Spain said a substantial bid had been tabled by Ferrovial.
The reports come at a time when Glasgow Airport bosses have worked hard to bring new airlines and routes to west Scotland.
Their efforts saw the airport complete three continuous years of growth by the end of last year when more than seven million passengers used the terminal buildings.
This year is also expected to generate bumper business, with passenger numbers boosted by the Ryder Cup, Homecoming events and Glasgow hosting the 2014 Commonwealth Games.