Consider a trade market with one seller and multiple buyers. The seller aims to sell an indivisible item and maximize their revenue. This paper focuses on a simple and popular mechanism--the fixed-price mechanism. Unlike the standard setting, we assume there is information asymmetry between buyers and the seller. Specifically, we allow the seller to design information before setting the fixed price, which implies that we study the mechanism design problem in a broader space. We call this mechanism space the fixed-price signaling mechanism. We assume that buyers' valuation of the item depends on the quality of the item. The seller can privately observe the item's quality, whereas buyers only see its distribution. In this case, the seller can influence buyers' valuations by strategically disclosing information about the item's quality, thereby adjusting the fixed price. We consider two types of buyers with different levels of rationality: ex-post individual rational (IR) and ex-interim individual rational. We show that when the market has only one buyer, the optimal revenue generated by the fixed-price signaling mechanism is identical to that of the fixed-price mechanism, regardless of the level of rationality. Furthermore, when there are multiple buyers in the market and all of them are ex-post IR, we show that there is no fixed-price mechanism that is obedient for all buyers. However, if all buyers are ex-interim IR, we show that the optimal fixed-price signaling mechanism will generate more revenue for the seller than the fixed-price mechanism.

翻译：考虑一个包含一个卖家和多个买家的交易市场。卖家旨在出售一件不可分割的商品并最大化其收益。本文聚焦于一种简单且流行的机制——固定价格机制。与标准设定不同，我们假设买家与卖家之间存在信息不对称。具体而言，我们允许卖家在设定固定价格前设计信息，这意味着我们在一个更广阔的空间中研究机制设计问题。我们称此机制空间为固定价格信号传递机制。我们假设买家对商品的估值取决于商品的质量。卖家可以私下观察商品的质量，而买家仅知其分布。在这种情况下，卖家可以通过策略性地披露商品质量信息来影响买家的估值，从而调整固定价格。我们考虑两种具有不同理性水平的买家类型：事后个体理性（IR）与事前个体理性。我们证明，当市场中仅有一个买家时，无论理性水平如何，固定价格信号传递机制产生的最优收益与固定价格机制相同。此外，当市场中存在多个买家且所有买家均为事后IR时，我们证明不存在对所有买家均服从的固定价格机制。然而，如果所有买家均为事前IR，我们证明最优固定价格信号传递机制将为卖家带来比固定价格机制更高的收益。