The European Commission’s competition authorities began separate, unannounced inspections of the premises of Finnish forestry firms UPM and Stora Enso on Tuesday.
A similar inspection was also launched at the premises of Metsä Fibre, part of the Metsä Group.
The inspections are related to commission concerns that companies in the wood pulp sector may have violated EU antitrust rules that prohibit cartels and restrictive business practices.
In a press statement, the EU commission said that the inspections are a first step towards an investigation into suspected anticompetitive practices, but do not necessarily mean that competition law has been infringed.
"The Commission has concerns that the inspected companies may have violated EU antitrust rules that prohibit cartels and restrictive business practices," the statement said, adding that inspections are being carried out at the premises of pulp companies located in several EU member state countries.
The Finnish Competition and Consumer Authority (KKV) will assist the commission in conducting the inspections within Finland, KKV's Research Manager Juuli Broms confirmed to Yle, but the authority could not comment any further.
However, Broms did say that, at a general level, unannounced inspections are standard practice in cases where there is a suspicion of illegal activity.
The commission did not disclose the names of the companies involved in the preliminary stages of the investigation, but news agency Reuters reported that the Swedish forestry company Holmen has not been contacted by the commission in its investigation of possible cartel activity in the wood pulp sector.
Stora Enso, UPM and Metsä Group are all big players within the forestry sector on a Europe-wide scale, with Finnish and Swedish companies dominating the market.
Companies' share prices decline
The share prices of Stora Enso and UPM both fell by about 4 percent on the Helsinki Stock Exchange on Tuesday afternoon as reports emerged of the inspections.
Similarly, the share price of Metsä Board, which is part of the Metsä Group, fell by more than 5 percent. According to the latest information, Metsä Board will not be subject to any inspection, a Metsä Group press release stated.
The duration of the inspections is affected by many factors, the EU Commission said, but was not willing to elaborate further on their progress at this stage.