An extract from The Dominance and Monopolies Review - 7th edition
Market definition and market power
The first step in abuse of dominance cases is the definition of the relevant product and geographical market. The ICA's general approach to market definition is consistent with the Commission's practice (in particular, the ICA typically focuses on demand-side and supply-side substitutability). Similarly, the ICA follows the EU notion of dominance.
Market shares are a key factor in the assessment of dominance. Market shares exceeding 40 per cent are normally considered an indication of dominance. However, firms holding market shares lower than 40 per cent may also be dominant if the remaining part of the market is composed of small competitors. The stability of market shares is also important, but the fact that the market share is decreasing does not necessarily preclude a finding of dominance. In the assessment of dominance, the ICA and national courts may consider a number of additional factors that give the firm concerned a competitive advantage or raise barriers to entry.
A dominant position may be held by one or more firms. In accordance with EU case law, collective dominance may be based not only on structural or contractual links between the companies concerned, but also on the economic interdependence among firms active in an oligopolistic market.
Abuse of economic dependence in a contractual relationship with a single customer or supplier (relative dominance) is prohibited by Article 9 of Law No. 192/1998. This provision aims at protecting the interests of weak parties in contractual relationships. When a contested conduct affects competition on the market, the ICA may exercise its investigative and fining powers under the Competition Act, and it may apply both Article 9 of Law No. 192/1998 and Article 3 of the Competition Act.