Changes

An '''oligopoly''' is a [[market]] with only a few sellers, who enjoy [[Barrier to entry|barriers to entry]] against new [[competitor]]s.  An oligopoly lacks full [[competition]] and [[consumer]]s may suffer as a result.

An '''oligopoly''' is a [[market]] with only a few sellers, who [[colluded]] together to create [[Barrier to entry|barriers to entry]] against new competitors.  An oligopoly lacks full [[competition]] and [[consumer]]s may suffer as a result.

Described another way, an oligopoly is an [[industry]] or market dominated by only a few firms selling a similar (undifferentiated) product.  This is called a "perfect oligopoly."  The few firms can behave in a harmful manner similar to how a [[monopoly]] behaves in overcharging customers or otherwise suppressing beneficial competition, since a low number of dominant actors in the market makes it relatively easy for them to collude and form a [[cartel]].

Described another way, an oligopoly is an [[industry]] or market dominated by only a few firms selling a similar (undifferentiated) product.  This is called a "perfect oligopoly."  The few firms can behave in a harmful manner similar to how a [[monopoly]] behaves in overcharging customers or otherwise suppressing beneficial competition, since a low number of dominant actors in the market makes it relatively easy for them to collude and form a [[cartel]].