It is the first residential building that Ortega's firm has bought outside the United States, Pontegadea said, adding it was part of its strategy to invest in multiple real estate assets.

The Opus 6 Hanover Quay building is at the heart of Silicon Docks, the nickname for Dublin's business and technology district, and offers luxury apartments and townhouses for long-term rent, according to the building's website.

The Irish Times, which earlier reported the deal, said the price was similar to the one paid by the building's previous owners, New York-based investment manager Angelo Gordon and his Dublin partners Carysfort Capital.

Ortega, the main shareholder of fashion giant Inditex and one of the world's 30 wealthiest entrepreneurs, has previously purchased two residential skyscrapers with luxury flats in the U.S. cities of New York and Seattle.

Pontegadea has focused on investing in real estate assets worldwide and in Spain's energy infrastructure.

($1 = 0.9189 euros)

(Reporting by Corina Pons Editing by David Latona and Mark Potter)