The European Commission has said it has raided the offices of a number of companies involved in sports broadcasting and rights.
A unit of Rupert Murdoch's Fox has said it is cooperating with the investigation.
"The Commission has concerns that the companies involved may have violated EU antitrust rules that prohibit cartels and restrictive business practices," the Commission said in a statement, after raiding offices in several member states.
"Unannounced inspections are a preliminary step into suspected anticompetitive practices. (It) ... does not mean that the companies are guilty of anti-competitive behaviour nor does it prejudge the outcome of the investigation itself."
Sports broadcasting has become a huge business in Europe and the United States, with networks spending billions of pounds to secure exclusive rights to show games in top-flight leagues to attract viewers.
The Commission did not name any of the companies affected.
Fox Networks Group, a unit of Murdoch's 21st Century Fox Inc, had said earlier that it was cooperating with the EC inspection.
FNG is an operating unit of Fox, which distributes TV and cable channels and content around the world.
