代工產業是台灣目前出口的主力，然而代工產品的銷售管道通常都掌控在國際知名或大廠商的手上，導致後者可以利用專買或寡買的優勢決定產品代工的價格。在這篇文章裡，我們發現代工出口國家的最適貿易政策乃是對其產品課徵出口稅。但是，只要代工業者具有開拓市場的能力，或是能夠取得其他的銷售管道時，最適的出口政策則是採用出口補貼。本文還討論了跨國企業擁有自製生產與代工的情況，我們發現上述政策建議在讓代工市場的買賣雙方都擁有替代選擇的情況下依舊成立。

The majority of Taiwan’s export industries are under contract to produce components for multinationals，which usually have established global brands and distribution channels around the world. Using their overwhelming buying-power in the world market for components， the multinationals have a dominant position and set an exploitatively lower level of prices in the international components market. In this article，we find that the government of an exporting country can use an export tax to counter the monopsony or oligopsony power of the multinationals. However， the optimal trade policy for exported components shall revert to an export subsidy once the component producers in the export country have outside options to sell their products to potential buyers， or to establish their own brands and sale channels. Meanwhile， we have extended the analytic model to a situation of bi-sourcing； that is， the multinational firms can manufacture a portion of their components in house (insourcing) and acquire the same inputs from external suppliers (outsourcing). We argue that the export tax/subsidy results still hold when the multinational firm is conducting the bi-sourcing strategy.