* Fraport buys Airmall in foray into U.S. airport retailing
* Airmall oversees 34,000 m2 retail space at 4 airports
* Airport retailing offers high margins
* Fraport does not disclose financial details
* Fraport shares down 0.7 pct, in line with market (Adds more details on retail business, CEO comment)
BERLIN, Aug 4 (Reuters) - German airport operator Fraport has bought a U.S.-based manager of retail space at four U.S. airports as it looks to expand its profitable retail operations and gain a foothold in the United States.
Fraport said on Monday it was buying 100 percent of AMU Holdings, which owns Airmall USA Holdings Inc, for an undisclosed price.
Airmall markets retail space at the airports of Baltimore, Boston, Cleveland and Pittsburgh, overseeing around 270 retail, food and drink outlets at the four hubs.
Airmall manages a total of around 34,000 square metres of retail space at the four airports. By comparison, Fraport's Frankfurt airport, Europe's third largest, has around 41,000 square metres of retail space with around 300 outlets.
Marketing space for retailers is a lucrative source of income for airport operators. In 2013, Fraport reported earnings before interest, tax, depreciation and amortisation of 880 million euros ($1.2 billion), of which 350.7 million came from its retail and real estate operations.
The retail and real estate segment had a margin on EBITDA of 74.8 percent, compared with 24.3 percent for Fraport's aviation unit.
"The retailing business at our Frankfurt home-base has always been a growth engine," Fraport Chief Executive Stefan Schulte said in a statement on Monday. "With the acquisition of Airmall, we have established a promising platform for developing our U.S. business in the future."
Fraport said that compared with European and Asian airports, many U.S. airports had some catching up to do when it comes to the services that they offer passengers.
Fraport, which also owns stakes in airports in Lima, Antalya, Varna and Burgas, currently has just one investment in the United States, a 100 percent-owned IT service company based in Orlando.