Bids by core investors valued the company at up to €8 billion, more than originally anticipated.
Enaire, which is selling 49 percent of Aena, said that an initial 21 percent stake would be sold to three shareholders, Corporacion Financiera Alba, Ferrovial and Britsh fund The Children's Investment Fund (TCI), who offered to pay between 48.66 euros and 53.33 euros per share.
The Children's Investment Fund, run by hedge fund billionaire, Chris Hohn, is best known for taking big stakes in companies and challenging management on strategy and performance.
Corporacion Financiera Alba is also a reference shareholder in Spanish infrastructure giant ACS.
The deal values Enaire at between 7.3 billion to 8 billion euros.
The final price paid by core investors will depend on the second phase of the privatisation, in which a 28 percent stake will be sold to institutions and retail shareholders in an IPO in late November.
Aena carries a debt of more than €11 billion. Aena's enterprise value is around 19 billion euros, according to broker Banc Sabadell. Aena announced a profit of 597 million euros for the first time in 2013.
Aena is the world's leading airport manager, moving 187.4 million passengers in 2013. The company runs 46 airports and two heliports in Spain and another 15 airports abroad, most in Mexico.
The four stand-out airports in AENA are Madrid, Mallorca, Malaga and Barcelona.