根據社會結構觀點,一個不完全競爭的市場可被視為是一種由多個小團體所構成的社會網絡。每一個小團體都是由幾家廠商所組織而成。而廠商之間不僅彼此競爭,也互相監視。本論文採用社會結構與社會網絡理論,探討過去社會學領域較少關注的廠商勾結行為,同時也為策略管理領域提供了廠商勾結行為的另外一種解釋。本論文假設小團體結構與社會結構特質–角色差異性及地位不一性,將影響群體間的競爭強度,從而影響群體內整體廠商的績效表現。進一步而言,本論文假設在一個穩定結構的小團體內,成員將具有高度的角色差異性與低度的地位不一致性,而這樣的小團體面對的將是較低度的群體間競爭。本論文採用了美國投資銀行業作為實證產業。研究樣本乃是取樣自1997至2006年間曾擔任普通股聯合承銷團之主辦銀行。以成對的主辦銀行過去互相參與承銷團的事件作為互惠關係的基礎,再由此關係建構起社會網絡結構–小團體,並以此來進行假設檢定。
From the social structure perspective, an imperfectly competitive market can be described as a social network made up of clique-like subgroups of firms that define each other as potential competitors and who monitor each other’s actions. This thesis employs the social structure and social network theory to provide an alternative explanation of a firm’s collusive behavior, an area rarely discussed in the sociological literature. This thesis postulates that the clique and social structural attributes, the role diversity and the position inequality, influence the intensity of competition which in turn affects firms’ performance. This thesis hypothesizes that members coordinated in a stable clique structure are more likely to show less intense competition with higher role diversity and less position inequality. This thesis uses the U.S.A. investment banking industry for its empirical setting. The samples are drawn from those investment banks that conducted underwriting businesses, serving as book runners and joint book runners for new issues of common shares in a syndicate from 1997 till 2006. The reciprocal relationship between two book-runner banks participating in each other’s syndicate construct the social network structure – cliques, which are then used to test the hypotheses of this thesis.