本論文建立一個垂直相關市場模型，討論一第三國上游廠商同時提供中間財給兩個不同國家的下游廠商時，若其中一個國家的廠商想要跨國銷售的情況下，貿易自由化對上游廠商的訂價與兩國社會福利的影響，本論文得到的重要結果如下。

當上游廠商採取單一訂價且關稅不會太高時，上游廠商為了增加廠商A跨國銷售的誘因，會降低中間財價格，在此情況下，貿易自由化使得廠商A進入B國銷售下，出口國消費者剩餘與進口國廠商利潤皆有可能增加，此外，進口國的社會福利一定比自給自足下為高。

 當上游廠商採取差別訂價，且兩市場規模差異不大時，若貿易自由化使得廠商A跨國銷售，進口國的消費者剩餘反而可能因廠商A的加入而減少，進口國廠商的利潤則因為廠商A的加入而一定減少，因此，自給自足下進口國的社會福利，可能高於貿易自由化使廠商A進入B國銷售下的社會福利。

This dissertation establishes a vertically related model to discuss when an upstream firm in the third country provides intermediate goods to two differentcountries’s downstream firms, the impact of trade liberalization on upstream firm’spricing and the two countries’ social welfare, If one downstream firm want to sell it’s product in the other country. Our findings are as follows.
When the upstream firm adopts uniform pricing and the tariff is not very high,the upstream firm will reduce the price of intermediate goods to induce firm Aexport it’s product to country B. When a lower tariff makes firm A sell it’s productin country A and B, the consumer surplus of the exporting country and the firm’sprofit of the importing country may increase. In addition, the social welfare of importing country must be higher than the case of autarky.
When the upstream firm adopts discriminatory pricing, and the market size oftwo countries are similar, the consumer surplus of the importing country may inversely decrease, if trade liberalization makes firm A sell in the other country, but the firm’s profit of the importing country will certainly decrease. By the reason, the social welfare of the importing country in the case of autarky may be higher than the case that firm A sell it’s product in the country B.

目錄


第 1 章 前言……………………………………………………………………1
第 2 章 基本模型………………………………………………………………6
      2.1 上游廠商單一訂價……………………………………………………6
      2.2 上游廠商差別訂價……………………………………………………8
第 3 章 貿易自由化……………………………………………………………10
      3.1 上游廠商單一訂價……………………………………………………11
      3.2 上游廠商差別訂價……………………………………………………14
第 4 章 福利分析………………………………………………………………21
      4.1 單一訂價下的福利分析………………………………………………21
        4.1.1 單一訂價下的兩國消費者剩餘…………………………………22
        4.1.2 單一訂價下的下游廠商利潤……………………………………23
        4.1.3 單一訂價下的兩國社會福利……………………………………24
      4.2 差別訂價下的福利分析………………………………………………25
        4.2.1 差別訂價下的兩國消費者剩餘…………………………………26
        4.2.2 差別訂價下的下游廠商利潤……………………………………27
        4.2.3 差別訂價下的兩國社會福利……………………………………29
第 5 章 結論……………………………………………………………………32
參考文獻……………………………………………………………………………34

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