Capacity Choice in a Large Market

We analyze endogenous capacity formation in a large frictional market with perfectly divisible goods. Each seller posts a price and decides on a capacity. The buyers base their decision on which seller to visit on both characteristics. In this setting we determine the conditions for the existence and uniqueness of a symmetric equilibrium. When capacity is unobservable there exists a continuum of equilibria. We show that the “best” of these equilibria leads to the same seller capacities and the same number of trades as the symmetric equilibrium under observable capacity.本文针对商品完全可分割（perfectly divisible goods）的大型摩擦性市场（frictional market），研究内生产能形成（endogenous capacity formation）问题。在此市场中，每位卖家需制定价格并确定产能，买家则依据价格与产能这两项特征选择光顾的卖家。本文推导得到该设定下对称均衡（symmetric equilibrium）存在且唯一的条件。当产能不可观测（unobservable）时，市场存在连续统均衡。本文证明，此类均衡中的"最优"均衡，其对应的卖家产能与交易数量，与产能可观测场景下的对称均衡完全一致。