On 17 February 2007 KAUČUK, a.s. and UNIPETROL, a.s. lodged legal charges with the European Court of First Instance against the European Commission's decision of 2006, which imposed on both of them a fine of EUR 17.5 million for their involvement in a synthetic rubber cartel. According to the Commission, cartel agreements on prices were made and sensitive information was exchanged between the competitors during meetings of the European Synthetic Rubber Association (ESRA) in years 1999 -2002. Kaučuk did not take part in these meetings directly but through its trade representative. Unipetrol was included in the enquiry only because it is Kaučuk's parent company.

In their charges, Unipetrol and Kaučuk challenge the Commission's decision to the full extent. Both companies concur that the evidence does not indicate that Kaučuk's trade representative took part in any anti-competitive practices. Moreover, in Unipetrol's case responsibility for the cartel, if any, is ruled out, if only because it does not operate on the rubber market and was not even a member of the ESRA. The mere fact that it is a parent company of Kaučuk cannot constitute sufficient grounds for establishing responsibility for cartel practices.