First, oligopoly compares with monopoly as they both operate in markets that have imperfect competition. They also compare that due to substitution options and the elasticity in prices, they both have demand curves sloping downward. Additionally, they both offer companies in these competitive market control over the market.

Oligopoly and monopolistic markets compare in this way, the firms involved in the two exchanges can collaborate to charge prices high and earn more profits as they have control.

Oligopoly and perfect competition correlate in that both are market structures, and in both markets, small firms exist, and there is no sole controller of the market.