本文建立一個獨占性競爭總體模型來探討在長期下,當廠商可以自由進出,使廠商家數內生化後,分析總體變數在不完全競爭商品市場為垂直分工和垂直整合制度之間的相對表現。我們發現幾個重要的結論:第一、在垂直分工下,獨占力程度的大小與廠商家數會有不確定的情況;反之,在垂直整合下,獨占力程度的大小與廠商家數有正向關係;第二、不管獨占力程度的大小,在垂直分工下實質利潤為正;第三、不管獨占力程度的大小,家計單位福利水準在垂直整合下比垂直分工大;第四、不管獨占力程度的大小,廠商家數在垂直整合下比垂直分工大,且假設其他條件不變下,廠商家數差異與獨占力程度有正向關係且是遞增趨勢。
This paper incorporates the endogenous firm’s numbers into a monopolistic competition macroeconomic model and investigates the determination of long-run macro variables under both vertical separation and vertical integration regimes. Some important results are obtained by analyzing and comparing two different industrial structures. First, under vertical separation, the relationship between the degree of monopoly power and the firm’s number is uncertain. However, under vertical integration, a higher degree of monopoly power tends to generate a higher level of the firm’s number. Second, under vertical separation, real aggregate profit is positive regardless of the degree of monopoly power. Third, the household’s welfare level under the vertical integration regime is greater than that under the vertical separation regime regardless of the degree of monopoly power. Fourth, the firm’s number under the vertical integration regime is greater than that under the vertical separation regime regardless of the degree of monopoly power, and other things being equal, the difference of firm’s number between vertical integration and vertical separation is positively related to the monopoly power and convex in the monopoly power.