Not only the agreements between direct competitors (horizontal agreements) but also vertical agreements between undertakings acting at different levels of distribution chain, for example supplier – customer may have the anticompetitive effect. (Detailed specification of prohibited agreements is included in the article 4, par. 3 of the Act on Protection of Competition). This could include, for example, agreements on exclusive distribution or the agreements conclusion of which is conditioned by adoption of other commitments which do not refer to the subject of these contracts by their nature or according to the usage of trade. Not all vertical agreements are contrary to the Act on Protection of Competition, either because the impact on the market is not significant or the positive effects outweigh their negatives.