社會福利，產出配置與要素市場差別訂價

Welfare, Output Allocation and Price Discrimination in Input Markets

本研究分析上游獨占廠商訂價策略對最終財產量分配及社會福利的影響。假設要素市場存在一獨占廠商將其生產的中間財銷售給下游的多家獨立零售商（local retailer）生產最終財。每一個最終財市場中存在一家獨立零售廠商與一家向後整合的連鎖廠商（backward-integrated chain store）進行數量競爭。不同於過去文獻的結論，本文發現上游獨占廠商在採取差別訂價時對刀效率的零售廠商可能收取較低的要素價格。此外，我們也發現當配置效率的正效果高於生產效率的負效果時，即使總產量不變，要素差別訂價亦有可能提高社會福利。本文的發現與一般文獻上認為中間財差別訂價有損社會福利的看法有很大的不同。且此一結論在連鎖廠商沒有向後整合的情形之下仍然成立。

We analyze the price decision of an upstream monopolist who produces and sells an intermediate good to downstream markets where a backward-integrated chain store competes with many local retailers. It is shown that the upstream monopolist may charge a more efficient local retailer a lower input price under price discrimination. This finding is of interest as it goes against the standard conclusion in the input price discrimination literature. Moreover, contrary to the general findings in the literature in which input price discrimination is welfare-deteriorating, we find that input price discrimination improves social welfare if the positive output allocation efficiency effect outweighs the negative production efficiency effect. These results are robust even if the chain store is not backward integrated.