Strategic behaviour by a firm or group of firms to restrict market access possibilities of potential competitors either upstream or downstream. Foreclosure can take different forms, from absolute refusal to deal to more subtle forms of discrimination such as the degradation of the quality of access. A firm may, for example, pre- empt important sources of raw material supply and/or distribution channels through exclusivity contracts, thereby causing a foreclosure of competitors.

Source: Glossary of terms used in EU competition policy, Antitrust and control of concentrations, European Commission, 2002