A cartel is a formal (explicit) “agreement” among competing firms. It is a formal organization of producers and manufacturers that agree to fix prices, marketing, and production. (…) The aim of suchcollusion (also called the cartel agreement) is to increase individual members’ profits by reducing competition.
Competition laws often forbid private cartels. Identifying and breaking up cartels is an important part of the competition policy in most countries, although proving the existence of a cartel is rarely easy, as firms are usually not so careless as to put collusion agreements on paper.
All of the above competing companies offer 4 months at 50% discount and exact same prices (within a margin of Eur 0,01)
See also (Portuguese legislation forbidding collusion):
Práticas restritivas da concorrência
Tipos de práticas restritivas
Acordos, práticas concertadas e decisões
de associações de empresas
– a clear exhibition of the publicly available information from the companies
– a definition exert from Wikipedia.
– a quotation of the legislation