This is illustrated in Figure 1, where A is dominant in the upstream market and tries to foreclose access of an actual or potential upstream rival B to customers such as X and Z in the downstream market.
Foreclosure of competitor by denying access to customers downstream 71. In some situations there is more than one upstream market. The dominant company A typically is or wants to be present on all of these markets while B may be present on only one or a few of these adjacent markets. The concern may then be that A is trying to exclude B from one or more of these markets through foreclosing its access to the downstream customers X and Z, for instance through tying the products from the various upstream markets. This, however, does not change the basic point that A is trying to exclude an upstream rival from one or more of the upstream markets.
Group 2, refusal to supply & margin squeeze
72. The second group of abuses consists of refusal to supply, which here includes margin
squeeze cases. Whereas the aim in the situations described above is to exclude B, a rival in the upstream market, in the typical refusal to supply case the aim is to exclude an already active or a potential participant in the downstream market, for instance Z (vertical foreclosure). From a competition policy point of view, this is mostly only a worry if the dominant company A is itself