The watchdog fined the six £90m. The other companies are Gorazdze Cement SA, a unit of Germany's biggest cement maker, Heidelberg Cement AG; another German cement maker, Dyckerhoff AG; and Polish producers Cementowania Warta SA and Cementowania Odra SA, the regulator said.
The antitrust office started its investigation in 2006 and said in a statement at the time that it suspected some market participants of fixing prices and sales levels. It raided offices of eight cement producers and three other companies in May that year.
Five of the six producers were fined the maximum possible of 10% of their annual revenue, while Gorazdze will pay 5% of its revenue, because it co-operated on the case with the regulator, the watchdog said without detailing the individual penalties.
Lafarge SA, the world's biggest cement maker, although it also participated in the cartel was not fined because it helped in the investigation. The seven companies controlled the Polish market, the watchdog said.
Illegal agreements are very often concluded on the construction market. The sector is carefully observed by the European Commission, which carried out the wide-ranging inspections of the undertakings operating on the market in a couple of member states in 2008 and in Spain in 2009. In 1994 in a record decision, the Commission fined 42 undertakings from 16 countries taking part in pan-European agreement consisting in market sharing.