|摘要: || 本論文利用一個垂直相關市場模型，討論有一上游中間財廠商同時供應中間財給兩個不同產業的廠商時，若其中一產業的廠商有意跨足到另一產業的情況下，上游廠商的最適訂價策略，以及對社會福利的影響。我們不失一般性地令兩產業各有一家廠商A與B，其中廠商B為有意跨產業生產的廠商。本論文得到的重要結果如下。|
This dissertation uses a vertically-related market model to discuss when an upstream firm sells the intermediate goods to two downstream firms in different industries. Given one of the downstream firm in tend to cross industry and sell in the other market. We analyze the impacts on the upstream firm’s pricing and the social welfare. Let firm A is a downstream firm in market A and firm B in market B. Firm B is the firm intends to sell in both markets. The main findings in this dissertation are as follows.
First, under uniform pricing of the upstream firm a few cross-industry costs, the upstream firm will reduce the price of intermediate goods to induce firm B to sell in two markets. Given firm B decides to sell in markets, it is possible that the profits of the upstream firm, firm A, and B will increase. In addition, both markets consumer surplus and social welfare may also increase.
Second, under price discrimination of the upstream firm: (1) If the difference between these two markets’ size is small, and the firm B serves in both markets, the upstream firm’s and both of the downstream firms’ profits may also increase. But interestingly, the consumer surplus of market A and the social welfare may be lower when firm B serves in both markets. However, consumer surplus of market B may increase. (2) If the difference between these two markets’ size is large, even firm B serves only the market B, its’ profit may decrease, while the profit of firm A may increase. In this case, as the cross-industry cost is lower, the consumer surplus of market A and the social welfare will increase, however the consumer surplus of market B will decrease.