Speculative storage in imperfectly competitive markets

•Oligopolists strategically manipulate speculative behavior.•Speculators may squeeze consumers out of the market.•Producers' incentive to sell to speculators is non-monotonic in the number of firms.

Markets for many commodities are characterized by imperfectly competitive production as well as substantial storage by speculators who are attracted by significant price volatility. We examine how speculative storage affects the behavior of an oligopoly producing a commodity for which demand is subject to random shocks. Speculators compete with consumers when purchasing the commodity and then subsequently compete with producers when selling their stocks, resulting in two opposing incentives: on the one hand, producers would like to increase production to capture future sales in advance by selling to speculators; while on the other hand, they would like to withhold production to deter speculation, thereby eliminating the additional supply from speculators in future periods. We find that the incentive to sell to speculators can be quite strong, potentially resulting in prices sufficiently high to drive consumers from the market. Furthermore, these incentives are non-monotonic in the number of producers: speculative storage occurs more frequently in a relatively concentrated oligopoly than in the extremes of monopoly or perfect competition.