Stockpiling and Shortages (the “Toilet Paper Paper")

Widespread stockpiling of everyday household items (e.g., toilet paper) occurred in the wake of the Covid-19 pandemic, resulting in shortages of these items in stores. Both phenomena reinforce each other: The expectation of shortages causes stockpiling behavior, which in turn amplifies the shortages, which in turn encourages more stockpiling. In this paper, I examine this feedback loop. In the model, households want to consume one unit of a good per period, but can store more than one unit at a cost. Aggregate supply of the good may be insufficient to meet aggregate demand, but prices cannot adjust to equate supply and demand. I characterize stationary equilibria in which households maintain target inventories of z units. Thus, stockpiling arises if z > 1, and I demonstrate that this can be an equilibrium even for very small aggregate supply-demand imbalances. In particular, in many equilibria the incentive to stockpile is driven mostly by the stockpiling behavior of other households, and not by the fundamental supply shortage. Transitional dynamics are examined as well.