Buying from a Group
研究买方从一群成本信息私有的卖方处购买整体商品的最优机制，发现交易取决于买方收益是否超过卖方虚拟成本的加权平均，且权重偏向于事前不愿交易的卖方，该机制优于标价机制。
A buyer procures a good owned by a group of sellers whose heterogeneous cost of trade is private information. The buyer must either buy the whole good or nothing, and sellers share the transfer in proportion to their share of the good. We characterize the optimal mechanism: trade occurs if and only if the buyer’s benefit of trade exceeds a weighted average of sellers’ virtual costs. These weights are endogenous, with sellers who are ex ante less inclined to trade receiving higher weight. This mechanism always outperforms posted-price mechanisms. An extension characterizes the entire Pareto frontier.