(Adds details on debt, airports, share sale)
MADRID, July 22 Spain's state-owned AENA has appointed banks Santander, BBVA, Bank of America Merrill Lynch, Goldman Sachs and Morgan Stanley to run a process in which just under half the company will be privatised, the airport operator said on Tuesday.
Spain aims to sell up to 49 percent of heavily-indebted AENA, the world's biggest airports operator, through a placement of up to 21 percent with institutional investors and selling the remainder through an initial public offering.
The government has said the aim of the sale is to make the company more efficient and attract more tourist flights. AENA owns 46 airports at home and also has international interests such as a stake in London's Luton Airport.
The government is expected to net only about 2.2 billion euros ($2.97 billion) from the sale, given the company's debt of some 11.5 billion euros, according to calculations by sector experts. This is not enough to make a major dent in Spain's public deficit.
Just 13 of the 46 Spanish airports were profitable in 2013, including Madrid, Barcelona and tourist destinations such as Palma de Mallorca, Ibiza and Tenerife.
AENA made a profit of 597 million euros in 2013, after huge cost reductions including staff cuts and after benefiting from airport tax hikes, up from a 215 million euro loss in 2011.
Spain is the world's third-biggest tourist destination behind France and the United States. AENA is the biggest airport operator in the world in terms of passengers, handling 187.4 million travellers last year.
France and Germany have both partially privatised their airport operators. ($1 = 0.7418 Euros) (Editing by Louise Heavens)