市場力量和R&D對貿易福利之影響──以黃豆貿易市場為例

R&D, Market Power, and Trade—The Case of Soybeans

本研究將以黃豆貿易市場為例，利用兩階段決策過程來探討R&D、貿易及市場力量之間在理論與實證上的雙向關係。我們利用不完全競爭空間均衡模型(imperfect spatial equilibrium model)結合猜測變量方法(conjectural variation approach)來探討因為R&D所導致黃豆產出增加對國際黃豆市場的衝擊。實證數據支持主要的黃豆出口國皆屬價格接受者，而主要的進口市場則是不完全競爭市場。當R&D所導致黃豆產出增加時，不論進口國或是出口國皆增加貿易福利，然而貿易國家間的福利上升多寡則取決於該國的市場力量大小。

The relationship between R&D and market power is a two-way one. In this study, a two-stage decision process is developed involving R&D, trade, and market power both in theory and by using an empirical model that is applied to soybeans. The impact of an increase in R&D on the soybean yield is incorporated into the international soybean market using an imperfect spatial equilibrium model together with the conjectural variation approach. The empirical results show that the major soybean exporters are price-takers while some of the import markets are characterized by imperfect competition. As the R&D-induced technical change in regard to soybean yields is incorporated into this empirical model, the empirical results show that both importers and exporters benefit from this improvement in yields. However, the way in which the welfare of trading countries is distributed may depend on both the improvement in yields and their market power.