垂直相關市場與最適出口貿易政策

STRATEGIC TRADE POLICIES IN THE VERTICALLY RELATED MARKET

本文設立一兩國出口至第三國模型。二出口國中，一國擁有生產中間財技術的若干垂直整合廠商，另一國的若干廠商則擁有生產最終財的優勢，但須自對手國進口中間財。本文的主要發現如下。第一，擁有中間財生產技術的出口國可能對最終財出口課稅或補貼，其決定關鍵在於兩國間的產業結構，及此國垂直整合廠商出口中間財和最終財間相對獲利性的大小。第二，具有生產最終財優勢的出口國亦可能對最終財出口課稅或補貼，其決定關鍵只在於兩出口國的相對產業結構。第三，當最終財市場的獲利性較中間財市場相對夠大時，垂直整合廠商的利潤反而有可能因中間財運輸成本的提高而增加。本文兩出口國間的設定符合部分台灣和中國大陸間的貿易關係，因此本文的部分結論可作為政府訂定兩岸三通政策時的參考。

We consider the trade policies and transport costs in a setting where downstream firms in one country are fully dependent on vertically-integrated firms for supplies of a key input in the another country, and these downstream and vertically-integrated firms are engaged in Cournot competition in the third country. We show the optimal trade policy for both countries may be a subsidy or tariff on final export goods. The market structure between these two countries and the relative profit margins between the upstream and downstream market play an important role in deciding whether the policy is a subsidy or tariff. In addition, increasing the transport cost of intermediate goods may increase the profit of vertically-integrated firms. Some results of this paper can offer a new insight for regulators to deal with Cross-Strait trade problems between Taiwan and Mainland China.