An oligopoly is a market structure with a small number of firms, none of which can keep the others from having significant influence.

Morgan Stanley analysts Joel Crane and Tom Price wrote in a report published on Dec. 11 that major iron ore miners now have an incentive to exercise market power.

In particular, duopoly and oligopoly frameworks illustrate how firms’ strategic interactions, such as output and price decisions, profoundly influence market stability and efficiency.