本研究以Buehler & Schmutzler(2008)、Yin & Zuscovitch(1998)、Symeonidis(2010)為基礎架構，第一篇假設上游兩家、下游兩家的雙占市場結構；第二篇研究指出大廠主要投入於製程創新，小廠投入於產品創新；第三篇提出了交叉持股對廠商之影響。本文與上述三篇文獻不同在於，非垂直整合廠商在採取產品創新的情況下，進行交叉持股策略，並與垂直整合廠商相比較，探討持股比例增加對廠商之經濟變數有何影響，以及當市場規模擴大，若持股比例增加時，對經濟變數是否造成的更強勁的力道。研究結果如下：(1) 交叉持股對廠商利潤皆有利，尤其對上游廠商利潤提升效果最為顯著。(2) 若新產品市場規模擴大，則垂直整合廠商、持股廠商與被持股廠商之利潤皆會增加；若舊產品市場規模萎縮，則持股廠商利潤會增加，被持股廠商與垂直整合廠商之利潤會下降。(3) 市場規模變動時，若向下持股比例愈大，則對於廠商會有加速擴大或減少的作用。 This paper extend the model of Buehler & Schmutzler (2008) which assume that both the upstream and downstream of the market structure are duopoly. Referring to the Yin & Zuscovitch (1998) which studies the large firms tend to pursue process R&D, while small firms typically try to create a ‘surprise’ through product innovation. Referring to the Symeonidis (2010) which studies the impact of cross-ownership of firms. The primarily difference of this article and the above-mentioned three studies lies in the fact that we assumed the non-vertically integrated firm adopts cross-ownership strategy in the case of product innovation, and compared with the vertically integrated firms. The study want to discuss what the effect on the economic variables when the degree of cross-ownership and the market scale rise. The results are as follows: (1) The strategy of cross-ownership is beneficial to the firms’ profits, especially for the upstream firm. (2) When market size of the new products expands, it is beneficial to the firms’ profits. When market size of the old products shrinking, it is good to holding firm, but not good to others firm. (3) Vertical cross-ownership under the market size changes will strengthen or weaken the firms’ profit.
