Aena, which runs 46 Spanish airports, saw its shares rocket as high as 17 percent on the day the company listed on the Madrid stock market, in Spain’s biggest initial public offering (IPO) since 2007.

The biggest airports group in the world in terms of passenger numbers finalised its shares at €58 a share - valuing the group equity at €8.7 billion. However, the IPO was five times oversubscribed and shares jumped as high as €68 - €10 above the issue price.

The IPO was initially scheduled to proceed last November, but had to be pulled last minute over fears over the Eurozone economy.

A surge in investor demand for Spanish assets and the delay in the IPO has proved highly beneficial for the Spanish government – the original IPO plan predicted a lower price range, with shares estimated at somewhere between €41.50 and €53.30.

Some 44.6 percent of Aena's share capital is being sold, with the majority offered to institutional investors and a small amount to retail investors. An overallotment portion may push that up to 49 percent.

Aena operates hubs in Madrid, Barcelona and Valencia, as well as smaller Spanish facilities in Malaga, Menorca and Bilbao. Outside of Spain, the company facilitates hubs in the Canary Islands, as well as London Luton, and some airports in Latin America.

The government had initially planned to sell 21 percent of Aena’s stock to three anchor investors including TCI, a UK hedge fund, Grupo Alba, a Spanish fund, and Ferrovial, a Spanish infrastructure group who is the largest shareholder in London’s Heathrow.

However, the increase in demand for Aena’s IPO meant the offer price escalated above what the three investors had committed to pay.

In December, the company's airports handled 12.3 million passengers. By comparison, the London Heathrow airport in the UK handled an average of 6.1 million passengers.

Aena's nine-month results last month showed the benefits of a restructuring to prepare it for privatization. Core earnings rose 15.5 percent to €1.46 billion, and Spain became the world's third most-visited nation in 2014, with 65 million visitors.

The Spanish economy rebounded in 2014, growing by 1.4 percent, and is forecasted to expand by 2 percent this year- above the euro zone average of 1.2 percent.

Aena destination map