Control of concentrations is regulated by the Prevention of the Restriction of Competition Act (Competition Act), which implemented Council Regulation (EC) No. 139/2004 (EC merger Regulation).

The concept of concentration as provided in article 10 of the Competition Act shows that a concentration is deemed to arise where a change of control on a lasting basis results from the merger of two or more previously independent undertakings or parts of undertakings; the acquisition of direct or indirect control of the whole or parts of one or more other undertakings; or the creation of a joint venture by two or more independent undertakings, performing on a lasting basis all the functions of an autonomous economic entity.

 A concentration must be notified if  (i) the combined aggregate annual turnover of all the companies concerned, including the affiliated companies, exceeded €35 million before tax in the Slovenian market in the preceding financial year; and (ii) the annual turnover of the target, including the affiliated companies, exceeded €1 million before tax in the Slovenian market in the preceding financial year; or (iii) in cases of joint ventures, the annual turnover of at least two companies concerned, including affiliated companies, exceeded €1 million before tax in the Slovenian market in the preceding financial year.

Regardless of the matched thresholds, the concentration does not need to be notified if it is subject to review of the EC Commission under the Regulation 139/2004/EC.