The link is defined in Northern Pacific Railway Co. v. United States (1958) as “an agreement of one party to sell a product, but only on the condition that the buyer buys another product (or bound) or at least agrees not to purchase that product from another supplier.” In addition to binding agreements, anti-competitive practices may include market distribution, boycott, supply manipulation, dumping, exclusive transactions, pricing, denigration and the collection of unethical business information. For competitive reasons, a monopoly may use forced purchases or tie-in sales to make sales in other markets where it is not dominant and to prevent competitors from selling in those markets. This may limit consumer choice for buyers who wish to purchase a product (“link”) by requiring them to purchase a second product (“linked”). As a general rule, the “linked” product may be a less desirable product that the buyer may not purchase, unless he is obliged to do so or it is preferable to receive from another seller. If the seller offering the related products has sufficient market power in the “binding” product, these agreements may violate the law of the agreements. The binder is usually illegal when products that are connected do not have a natural relationship, although there are exceptions. The argument is based on the fact that the consumer is aggrieved when he is forced to buy an unnecessary good (known as the linked property) just to earn the right to buy a desired good (also known as good property). Companies participating in the engagement may do so because the power of their market share, the overwhelming demand or the critical nature of a product may outweigh the limiting factor of competition in the market. In this case, the commitment can support the production and market share of lower quality products. Attaching is the “practice of a supplier of a product, the binder, which also requires a buyer to buy a second product, the linked product.” [25] The commitment of a product can take many forms[26], contractual commitment[27] when a contract requires the buyer to: Refuse to buy the two products together, refusal of delivery until the buyer agrees to buy both products, withdrawal or withholding of a warranty if the dominant seller only has the benefit of the guarantee when the seller accepts the purchase of that product[28] the technical link occurs when the products of the dominant party are physically integrated and the purchase of one is impossible without the other[29] and when two products are sold in the same package at a price. These practices are prohibited by Article 101, paragraph 1, point e) and Article 102, paragraph 2, point (d), and may terminate a violation of the statute if other conditions are met.

It should be noted, however, that the Court of Justice is prepared to find an offence that goes beyond that of Article 102, paragraph 2, point (d), see Tetra Pak/Commission. [30] Another important case in which it was a claim of recognizance was United States v.