Atlantia now owns 4.73% in Cellnex, down from 5.98% before the capital increase, a CNMV filing showed.

This summer, Cellnex raised 4 billion euros by selling new shares to finance the expansion of its telecom infrastructure network.

The capital increase dropped the stake held by the family of Italian billionaire Luciano Benetton to 13% from 16.45% though they remained the largest shareholder.

The Benetton family is also Atlantia's largest shareholder.

Spun off from Spanish infrastructure operator Abertis in 2015, Cellnex has expanded quickly and now has a market capitalisation of around 25 billion euros.

(Reporting by Inti Landauro; editing by Jason Neely)