Competition Among Companies: Coexistence and Extinction
  We study a spatially homogeneous model of a market where several agents or companies compete for a wealth resource. In analogy with ecological systems the simplest case of such models shows a kind of "competitive exclusion" principle. However, the inclusion of terms corresponding for instance to "company efficiency" or to (ecological) "intracompetition" shows that, if the associated parameter overcome certain threshold values, the meaning of "strong" and "weak" companies should be redefined. Also, by adequately adjusting such a parameter, a company can induce the "extinction" of one or more of its competitors. 
Marcelo Kuperman And Horacio Wio