中文摘要
政策制定者经常利用价格管制来应对其所管控市场中的不平等。本文从机制设计的视角考察此类政策的最优结构。我们研究一个买方与卖方交易的市场，其中经济主体对自身关于某一不可分割物品的估值以及自身的货币边际效用均拥有私人信息。规划者寻求一种机制，在满足激励约束和市场出清约束的条件下，最大化经济主体的总效用。我们通过识别配置效率与再分配之间的最优权衡，刻画受约束的帕累托前沿。我们发现，竞争均衡配置并不总是最优的。当市场买卖双方之间存在不平等时，最优设计会采用一种类似税收的机制，在买方价格与卖方价格之间引入楔子，并通过总额支付将由此产生的剩余再分配给市场中较贫穷的一侧。当市场同一侧内部存在较大程度的不平等，且这种不平等能够通过市场行为揭示时，实施价格管制可能是最优的，即便这样做会导致配给。
Abstract
Policymakers frequently use price regulations as a response to inequality in the markets they control. In this paper, we examine the optimal structure of such policies from the perspective of mechanism design. We study a buyer‐seller market in which agents have private information about both their valuations for an indivisible object and their marginal utilities for money. The planner seeks a mechanism that maximizes agents' total utilities, subject to incentive and market‐clearing constraints. We uncover the constrained Pareto frontier by identifying the optimal trade‐off between allocative efficiency and redistribution. We find that competitive‐equilibrium allocation is not always optimal. Instead, when there is inequality across sides of the market, the optimal design uses a tax‐like mechanism, introducing a wedge between the buyer and seller prices, and redistributing the resulting surplus to the poorer side of the market via lump‐sum payments. When there is significant same‐side inequality that can be uncovered by market behavior, it may be optimal to impose price controls even though doing so induces rationing.