structure of the market in question.45 It follows that the structure of the market and the way in which undertakings interact on the market may give rise to a finding of collective dominance.46
Oligopolistic Coordination 47. Undertakings in oligopolistic markets may sometimes be able to raise prices substantially above the competitive level without having recourse to any explicit agreement or concerted practice. Coordination is more likely to emerge in markets where it is relatively simple to reach a common understanding on the terms of coordination. The simpler and more stable the economic environment, the easier it is for undertakings to reach a common
understanding. Indeed, they may by able to coordinate their behaviour on the market by observing and reacting to each other’s behaviour. In other words, they may be able to adopt a common strategy that allows them to present themselves or act together as a collective entity. Coordination may take various forms. In some markets, the most likely coordination may involve directly coordinating on prices in order to keep them above the competitive level. In other markets, coordination may aim at limiting production or the amount of new capacity brought to the market. Firms may also coordinate by dividing the market, for instance by
geographic area or other customer characteristics, or by allocating contracts in bidding markets. The ability to arrive at and sustain such co-ordination depends on a number of factors, the presence of which must be carefully examined in each case.
Conditions for interdependence work – 1) Ability to monitor chiseling 48. Firstly, each undertaking must be able to monitor whether or not the other
undertakings are adhering to the common policy. It is not sufficient for each undertaking to be aware that interdependent market conduct is profitable for all of them, because each undertaking will be tempted to increase his share of the market by deviating from the common strategy. There must, therefore, be sufficient market transparency for all undertakings concerned to be aware, sufficiently precisely and quickly, of the market conduct of the others.47
See Joined cases C-395/96 P and C-396/96 P Compagnie maritime belge transports, cited in footnote 4, paragraph 36. See also the Commission’s Guidelines on the assessment of horizontal mergers under the Council Regulation on the control of concentrations between undertakings, OJ C 31, 05.02.2004, pp. 5-18, paragraphs 39-57. See Case T-342/99, Airtours plc v Commission  ECR II-2585, paragraph 62, and Case T-193/02 Piau, cited in footnote 6, paragraph 111.