The European Commission has conducted unannounced antitrust inspections in the data centre construction sector, it said in a statement.
It did not specify which companies were subject to the inspections but added that it is investigating a possible collusion in the form of no-poach agreements.
It added that it had also sent out formal requests for information to several other unspecified companies active in the same sector.
"The Commission has concerns that companies in the data centre construction sector may have violated EU antitrust rules that prohibit cartels and restrictive business practices (Article 101 of the Treaty on the Functioning of the European Union)," it said in a statement.
"The Commission is particularly investigating a possible collusion in the form of no-poach agreements. The Commission officials were accompanied by their relevant national competition authority counterparts."
The Commission added that the fact it carries out such inspections does not mean that the companies are guilty of anticompetitive behaviour nor does it prejudge the outcome of the investigation itself.
"The Commission respects the rights of defence, in particular the right of companies to be heard in antitrust proceedings," it said.
