21st Century Fox is the largest media player in Italy, according to a study from the communications regulator Agcom.
It contributed to total revenues within the sector of €17.1 billion in 2015.
The majority of the 15.4% share is attributable to Sky Italia (15.1%), while Fox Network Group Italy adds another 0.3%.
Next in line is Fininvest of which Mediaset contributes 13.3%, followed by the Italian public broadcaster RAI on 13.7%.
The position of Mediaset will be taken into account as part of Agcom’s probe into whether Mediaset shareholder Vivendi is in breach of competition rules. As the principal shareholder in Telecom Italia, the regulator wants to establish if the French conglomerate is in contravention of rules preventing a single company from holding significant shares in both telecoms and media companies.
Vivendi has been building a share in Mediaset since a public spat over the ownership of DTT pay platform Mediaset Premium.