政府制訂政策時往往有許多考量，尤其是面對外人直接投資時，政府的政策規範常會因為國內發展情況不同而有所調整，本文嘗試站在政府的角度，以兩種情況討論關稅的訂定與開放外人直接投資的決策。首先，我們以Grossman ＆ Helpman (1994) 之政治獻金模型為架構，考慮兩國廠商各種遊說的情況，藉以訂出最適關稅。我們發現，政府將會選擇兩國廠商一起遊說。其次，我們考慮本國政府可以開放外國廠商進入本國直接投資，同時我們假定外國廠商擁有技術優勢，進入本國直接投資後，對本國廠商會產生一技術外溢效果 (Spillover effect)，使得本國廠商邊際生產成本下降。最後，我們比較上述兩種情況之下之政府效用大小，並發現本國政府越重視國內福利相較於政治獻金時，將會傾向開放外人直接投資。 / Since the domestic government can choose the optimal policy instrument to maximize the social welfare, this paper analyzes how a domestic government sets the policy about foreign direct investment. In the beginning, we use Grossman ＆ Helpman (1994) political contribution model to endogenize tariff policy in a duopoly composed of a domestic firm and a foreign firm, where both firms affect the domestic government’s tariff policy via their contributions. It is found that the domestic government will choose both the domestic firm and the foreign firm apply contributions. Then, we consider a spillover effect when the domestic government decides to let the foreign firm with superior technology undertake foreign direct investment. Finally, we compare the government’s utility in the two situations above and find that the domestic government tends to open FDI when it puts much weight on the social welfare.

政府在制定政策的過程中，往往會受到利益團體影響。我們藉由 Grossman and Helpman (1994) 所發展的政治獻金模型為架構，討論在國內生產具有負面外部性的情況下，政府決定是否開放具有生產優勢的外國廠商進入本國生產的決策。我們發現開放外人直接投資與否，受到政府對社會福利重視的程度所影響。在政府極端不重視社會福利且生產完全無生產技術外溢時，政府將不會選擇開放國外廠商進入本國投資，而一般情況下，當市場規模夠大且政府重視社會福利有一定程度時，生產時所造成的負面外部性愈大，本國政府將傾向不開放外國廠商進入本國直接生產。 / Since the domestic government can makes its choice between alternative policy instruments to maximize its’ welfare, this paper analyzes how a domestic government makes the policy about foreign direct investment by Grossman and Helpman (1994) political contribution model. It shows that opening FDI or not is affected by the weight that the domestic government puts on the social welfare. We found that domestic government tends not to open FDI when it puts little weight on the social welfare. In this case that the weight and market are large enough, the domestic government tends to open FDI as the pollution externality increases.