本文利用一三國模型來分析政府最適產業政策與廠商垂直整合策略之關係。給定本國與外國各存在一中間財廠商與最終財廠商，且兩國之最終財廠商將產品出口至第三國市場從事數量競爭，本文指出在給定廠商整合有一固定之整合成本下，當整合成本相對地高，本國政府最適產業政策為對中間財做補貼、對最終財做課稅，此一稅制結構會誘使本國上下游廠商進行垂直整合。 值得一提的是，在此一均衡下，我們發現本國政府對中間財之補貼效果大於對最終財之課稅效果，因此垂直整合廠商不會買賣中間財，所生產之中間財全部生產最終財，外國上游廠商獨占上游市場，並造成中間財及最終財價格降低，本國中間財產出增加、外國中間財產出減少，而兩國最終財產出皆會增加。 This paper considers a three country model that analyze the relation between government optimal industrial policy and vertically integrated firm.Given the existence of a intermediate good and a final good firms in domestic and foreign country and final good firms export good to the third market with Cournot competition,this paper points out that integrated firm must pay fixed cost,when fixed cost relatively high,the domestic government must choose to subsidize intermediate good,but tax final good,under domestic government optimal industrial policy will induce upstream and downstream firms vertically integrate. Under this equilibrium, we find that the effect of subsidies for intermediate good is greater than the effect of taxes for final good and therefore vertically integrated firm does not participate in the intermediate good market, foreign upstream firm monopolizes the upstream market,the decrease of the prices of intermediate good and final good,the increase of domestic intermediate good output,the decrease of foreign intermediate good output, the increase of both countries final good output.
